Troop situation relating to Synapse seems a bit worse than I thought...
If termagants fail their instinctive behavior (ld6 check) they have a 50/50 shot of going into fall back mode. So clearly they can't play the "cultist role" (deckchairs). I was thinking that Hormagaunts' behavior in that situation was to Go to Ground (which would probably at least leave them where they were, making them at least still on the objective). But I was wrong, they are "Feeders" not "Hunters", so if they fail their ld6 check, they hit themselves, which will most of the time in turn force a morale check, which will then also make them fall back. So they're even worse at this job than termagants are.
Seems like there's no choice, you HAVE to either just run genestealers as fragile, 70pt objective claimers with no guns (which IMHO makes the idea of playing the army in an objective game absurd), or you need to have a synapse plan.
One man's guess: I bet people the people that try to play Tyranids competitively will STILL run Tervigons, even though they went up in price by 25% and are about half as good as they were in the old codex.
It's either that or Warriors (the same as they were in last codex, and when was the last time you saw one of these mythical beasts on the table? I can honestly say that I've never seen a Tyranid warrior in person)... I mean, what else is there? I'm gonna try a squad of Warriors myself. At least they won't run away on their own and don't require a 300 pt investment.