So I finally got my hands on the new Tyranid codex (actually pried it from the girlfriend while she slept) I have to say, somehow a couple shiney new monsterous creatures seem to have detracted from the fact that the codex overall seems to be much worse. This seems to be exactly the nightmare I envision with a new Dark Eldar codex.
Comparing the old book to the new really almost becomes comparing apples to oranges with the new book granting special abilities that weren't availble, and the old book granting very customizable broods. The one bonus of the new book, is straight line weapons, no more modifying by creature, so a devourer is now Str 4 Assault 3 across the whole army, great for Gaunts, hose for Tyrants. That may be the intangible that accounts for the gross points increase being forced upon the Nid players.
Here's an example, Tyranid Warriors, now have +1 WS, +1 BS, +1W,+1 attack, +1 save comes standard with a devourer and scything tallons. From the old book, warriors start at 14 points, and with all those same upgrades would cost exactly 30 points. The difference, old warriors have one more shot with a weaker devourer, new warriors re-roll 1's in CC, and a free +1 wound, but no Eternal Warrior. You are paying points up front to optimize for two roles.
The other thing that I find disturbing is alot of units have been gutted or modified to uselessness. Lictors and Hormagaunts are the ones that stand out the most for this. Lictors, while overpriced, were a great support, and harrassment unit. Now lictors are cheaper, and have an additional wound, but they were neutered in the process. No more 5+ cover all the time, only +1 to existing cover save, no feeder tendrils to help other units, and no assaulting after showing up. He's basically a trophy waiting to be collected. Hormagaunts are the same, as beasts they dashed quickly to the enemy line and tied them up until the rest of the swarm arrived. Now while they are a base of I5 and only 6 points, they only assault 6", with a slightly more reliable run. I'd be inclined to just take termagaunts with the 1 point upgrade for Furious Charge instead, they'll likely perform better with the +1 str, and shooting before they charge. This is huge in my mind, the army has no way to occupy opponents until the slow stuff gets close, except for maybe some gargoyles.
Of course, the slow stuff is now all normal sized because the Carnifex is a thing of the past. This is probably the most attrocious thing in the whole codex. You COULD take a brood of 3 Carnifexes. If you want to waste around 550 points. The basic Carnifex has a similar statline as before, +1 WS, -3 Ld, and re-rolls all misses with his twin scything talons. All this for the bargain price 160, a mere 50+ points more than before. Everybuild is hordes of points more expensive, and none come close the Str 10 T 5, 5 Wound beast that you could get for 160 points before. They completely neutered the Carnifex, which is sad because the kit is so beautiful, and I've seen so many great versions of the model. With most Nid players having multiple Carnifexes this should be a huge kick in the teeth, but it seems to have been salved by the nice new Trygon/Mawloc model. I expect alot of shelves to have matching Carnifex bookends.
The new MCs all seem to cost 150+ with the Heavy slots moving closer to the 200-250 range. Add to that the higher base cost of the Tyrant and you'll probably be seeing slightly less bugs on average as opposed to more. As far as better MCs, I'd be more inclinded to say they may not be better, but they are slightly harder to plan for in most cases. Of course if your army carries Agonizers, Dark Lances, and Disentegrators, don't sweat. Atleast until you hear rumors of them 'upgrading' our codex.