Here are the final biomorphs and weapons that need fixing for the Tyranid codex, and a couple of beasties I'd like to see. Though according to the latest rumors, there's 4 new creatures added. I guess it's already set in stone, but a guy can wish, can't he?
Bio-Plasma: I'd like it to use the flamer template with the strength dependent on several factors. If a unit uses it, the strength should be determined by the number of bugs in the unit, with every 4 granting one flamer template at S4. For MCs, the strength should depend on the creature's strength.
Thornback: Should probably grant the 'fex Furious Charge.
Symbiote Rippers: It never was that useful, but what if now it caused the model to be immune to "No Retreat" extra wounds? Fluffwise, the rippers would swarm and absorb blows intended for the leader-beasts.
Spore Cysts: I have taken this downgrade three times, in the hopes that it would reveal some great truth about life, the universe and everything; yet two of those 3 times, it killed my carnifex. The other time it created a vast wall of mines that prevented my opponent from claiming an objective, as he had to slow down his advance to deal with the mines. This is a fun choice, but it needs to get fixed as its use is pure luck.
Venom Cannon: I don't see why it should only inflict glancing hits. You can only take 3 of these at S10 in an army anyway, and the best BS they can get is 3. It would solve a lot of ranged attack problems.
Fleet: Tyranids used to be special because almost everything had fleet, now everyone can run so it's not a big deal. Gaunts don't need to fleet as they generally don't need to assault. Perhaps Tyranids should roll 2d6 for fleet/run and keep the highest.
Warp Field: Needs to be moved to at least a 5+ save. 6+ is just laughable.
New Creatures: I can think of two (besides a big artillery beast, but I already talked about that). One should be a transport type organism. Make it a fast moving MC with good armor and wounds, with the ability to carry a small brood. This will give us scoring MCs (if they are carrying troops), which would shift a lot of playstyles. The second is some kind of Brood Mother. This MC pumps out reinforcements like rippers and gaunts. Now that would be awesome.
So this ends my Tyranid wishlist section. In the next couple of months we'll probably start so see some rumors take shape, let's hope for the best!