Hello. I find most revisions of the Tyranids so far to be good and quite like the 9.1 version. I have some small irks however, and since you asked for them:
Model/stats inconsistency:
Lictors are big, and have macro-weapon.
Carnifexes are even bigger, and have macro-weapon.
Trygons are huge, their claws are massive and.... no macro-weapon. Instead they have +2 attacks for a total of 4. Allegedly, this is good, but still somewhat disappointing.
I would not die if lictors lost it and trygons got it. Lictors still have about every other special rule anyway
Units:
I think the ranged Carnifex should be available. Since most Tyranid players have to deal with conversions anyhow, I do not think models from a shelved range should be a limit.
Rules:
I find that dealing with Suppression makes Tyranid even more one-dimensional. In Tyranid 8.x Tyranids could not be suppressed and therefore your Tyranid warriors and Tyrants could fire away. In 9.1, you almost always have blast markers, taking away the little shooting your  swarms may have.
Suppression in combination with a complete lack of shooting also make failed activations really bad, accomplishing nothing. Other armies can at least shoot if they fail. Perhaps Synapse Creatures should not suffer from suppression.
Another option would be to give Gargoyles and Termagaunts a 15cm range. Then they could at least fire away. Not being able to engage (failing the initiative test) gives you zero options.
My 2 cents,
Fredmans
