Got my hands on a friend's copy of the new Tyranid Codex and more or less devoured the rules in one sitting.
My entry is somewhat brief, for a longer, unit-by-unit rundown, here's the link to "3++ is the new black" and his much longer, and much angrier, review:
First thoughts! A lot of effort seems to have been put into making the whole army more thematic and more fun to play (I'll let play testing get some time in before I make any claims about whether or not it's competitive)
Instinctive Behavior comes to mind here, the possible results (you roll a D6 for one of several results) of a unit being out of Synapse range are all very dramatic from what they used to be. Some units will immediately run away, others will hide (and potentially gain Stealth) while others will either gain Rage and go on a rampage or eat each other.
1.) No transport bug. No Mycetic Spore and nothing to replace it. Some of the Deep Striking units seem to have improved slightly (Lictor especially), but otherwise there's going to be some serious footslogging going on. Also, no Parasite of Mortrex, Doom of Malan'Tai, or Ymgarl Genestealers.
2.) Unique Psychic Powers, and no more access to the BRB powers (no more Endurance/Iron Arm Tyrants flying around). There are some interesting potential combos, and I like the extra flavor or having their own unique. It is a bit of a punch in the face to lose Biomancy...
3.) Points price drops. A LOT of points price drops. Taken individually it doesn't make that much difference, but combined it could have a dramatic impact on what combinations/units it's possible to field.
4.) Warlord Traits! Totally new, some very fun - from FNP (5+) the turn after taking a first wound, to making a single piece of Jungle terrain carnivorous (that one is situational, but cool if you can get it off). Note I said "fun" not "useful," very few of these are likely to come into play in the majority of games. But then, who knows?
5.) Old One Eye and Deathleaper are now HQs.
1.) Biomorphs are changed, Acid Blood for example is now S5, AP2, Ignores Cover (gnarly). Hive Tyrant upgrades are updated slightly (my personal favorite is making Fear rolls made against them be on 3d6 and discard the lowest, but they can also give a single Troop unit Outflank, and gain re-roll 1s for to-hit and to-wound in CC), Regeneration is, as rumored, a 4+
2.) Abilities have been adjusted to fit 6th Edition, for example, the Venomthrope's Spore Cloud now grants Shrouded to friendly units within 6"
3.) Hive Guard have their old gun (ignores LoS and all), but can also take a new gun instead. It sacrifices 6" range and 3 strength, but in exchange is a Blast with Haywire and AP5. Kind of meh, but against the right targets it could be ok.
4.) Crushing Claws are +1S, AP2, Armourbane and Unwieldly (this only matters to Tyrant Guard, as Carnifexes ignore Unwieldly and already have AP2 - but the +1S and Armourbane are both still nice, it means you don't have to sacrifice half of your attacks for Smash-style attacks)
5.) Hormogaunts now get a +3" bonus to their run moves.
6.) Zoanthropes now have Brotherhood of Psykers (Mastery Level 2) and cast Warp Blast once per member of the unit (so a unit of 3 casts it as Assault 3, with a single successful psychic test)
What do Eldar players need to watch out for?
Well, the 'Nids will still walk all over us in CC, either through sheer numbers of little bugs or with epic monstrosities. But, where they'll really get us is with Psyker bashing. Any bug with Shadow in the Warp will drop a Psyker's leadership by 3 (bringing even a mighty 10 down to a less-impressive 7) if they're within range, and any army fielding Deathleaper could drop that by another D3. Meaning, if you are supremely unlucky, your mighty Farseer could spend some (probably short, bloody, and inglorious) part of a game at Leadership 4. Try casting your trusty powers on that pile o' poo.
A somewhat funny thing, the new Codex also includes the Tyranids very own AA flyer, with limited-use missiles that re-roll to-hit vs. Flyers. It seems like a bit of a funny addition, but time will tell how good it is. The other Flyer offers a nasty suite of anti-Infantry/Light Vehicle air support that will have many armies running for cover.
In general, I get the feeling that the designers/writers of the Codex were aware that the 5th Edition Codex allowed for only a few truly successful builds, and those almost entirely circled around the old Iron Arm/Endurance Flyrants backed up by some other stuff. Things have been changed enough that other builds may now be equally viable, meaning more people will buy different models from good ol' GW, and we might see some more varieties of Bugs on the table!
He comes in at 40 pts. cheaper than he was before, with Crushing Claws and Scything Talons (for +1 attack for two pairs of weapons) along with Armourbane and S10.
He gets D3 Hammer of Wrath attacks at that S10, 5 attacks (with the +1 above, 6 on the charge) plus a tail attack, and for every successful hit in CC (not counting tail or HoW), he gets an additional attack (which doesn't grant another additional attack).
In addition, other units nearby can use his Ld., and he comes stock with the 4+ Regeneration and has the Warlord trait that grants him FNP (5+) in the turn following taking his first wound.
So, is he worth it?
He's still a giant pile of points and has the massive downside of taking an HQ slot without being a flying Hive Tyrant or Swarmlord (or even a Synapse creature). But, he has a huge pile of attacks, a decent save and FNP (if you take him as Warlord), and the 4+ regen. The amount of damage he can dish out solo is absurd, but he can still be shot to crap long before he gets in range. So, if you field him, make sure the other army is distracted!
...It is worth noting that because Synapse is so important in the new 'Dex, having the ability to use OOE's 8 Ld. is actually very handy for mobs with lower Leadership. It just might save the game once in a while (but not as much as another Synapse creature would have)
For fun games, I would still take him (and being me, I would still take him just because), but I seriously doubt he'll wind up being one of the better HQ options in the Codex.
Some further thoughts-
I just saw a quick Battle Report from Reecius over at Frontline again, and I was somewhat saddened by it (http://www.frontlinegaming.org/2014/01/11/warhammer-40k-video-bat-rep-new-tyranids-vs-eldau/). He more or less took his current army (shown by the beautiful paint and model work) and played as if nothing had changed, against the gnarliest opponent he could. It was, predictably, wiped out even when he cheated by 400 points and controlling his opponent's deployment.
And that's the biggest challenge here - a new Codex isn't a new paint job for your existing army. Especially the new 6th Codices have been throwing armies on their heads, and it's not going to work unless you build a list from scratch with that in mind.
So, biggest weakness of the new Codex we know fairly clearly: Synapse. If you lose Synapse coverage, things are going to go badly. So, invest some points in Synapse.
How about strengths? Tons of bodies and hard-hitting units. BUT, those units suffer from being almost exclusively short-range. They need cover (although don't rely on terrain because too many things ignore cover), they need target saturation, they need to get in there quick and make a mess.
What would I use?
1.) I think we're going to see more Zoanthropes being played now. Despite their total re-spec in the new Codex, they're still one of the best back-field Synapse options you've got. With a 3++ save and a small, more hide-able profile (and lower "kill it!" priority than others), and the frosting on the cake of likely rolling a buff power or two, they're the perfect support to your 'Nid tide. And, they're cheap.
...I must admit part of that prediction is that I freaking love Zoanthropes, but also I think they do have a defined role now as army buffer/Synapse glue unit.
2.) Trygon Primes. Again, Synapse, plus they get in the thick of things FAST. The big snake bugs (Mawlocs and Trygons) are easier to fit in an army now because of some points shuffling, and their role of keeping the heat off of your other stuff is even more vital. I love these guys too, and their ability to DS without worrying about terrain-biffing is a wonderful trait. Raveners are also worth taking in this regard, as terror units that can "cross" the field un-shredded.
3.) I would NOT invest heavily in Flyrants. Yes, they're amazing, but they're an incredible points-sink (even with the points reduction) and might as well be magnetized for enemy fire at the rate *everything* is going to shoot at them. Tough as they are, they're not as tough as most of the Flyers that Skyfire defenses are prepared for (and they're usually up front), so try spreading those points elsewhere. A non-flying Tyrant can also grant a single Troops unit Outflank, which has been underestimated as a tool. It allows you to take, say, a wall of Hormogaunts or Termagants and put them straight into the enemy deployment zone while avoiding at least a few turns of fire. Termagants might be a better choice because they suffer less from losing Synapse...
4.) Hive Guard. Who doesn't love Hive Guard? They took a bit of a hit, but being able to fire and Ignore Cover out of LoS is brutal. Use these bad boys, but keep them behind things that keep them out of sight.
5.) The Harpy. The Crone appeals to a lot of players, especially as an AA choice, but where the Tyranid flyers really excel (if at anything) is the ability to lay down pinning Large Blasts on those pesky infantry in hard-to-reach places.
6.) Biovores. They're cheaper and better, still have Barrage and can cause pinning. If you want covering fire for your advancing swarm, these guys will be invaluable.
7.) Genestealers. Ok, probably not, but they are a troop unit that can infiltrate, and a small unit of them can even be hidden somewhere where they won't be splattered immediately. And, who knows, maybe the other guy will be laughing too hard to remember that they are still dangerous?
Those are my initial, utterly untested, thoughts. I will happily eat any and all of those words that prove to be wildly incorrect - not, however, until after proper testing. And, on the note of proper testing, good ol' Reecius did throw down the gauntlet. Here's his challenge:
That's it for now, I'll chime in with more tidbits as they come up - and I promise I'll be back to the Eldar soon!