One big one (for me at least) is some clarification as to how Mawlocs and Reserves work. Most people will say that entering into "Ongoing Reserve" means that he has to walk on the board edge the following turn, despite the fact that RAI this clearly isn't the case. I mean, it's basically the exact same argument people had in 5th edition when CLEARLY RAI meant you could deep strike onto someone while all non Nid players said you couldn't. Really there are quite a few things like Spore Mines and Pyrovores (among others) that need to be address. I think its silly calling this book "one of the tightest codexes ever written". One would hope when you copy and paste the previous book and remove all the special rules it might be "tightly written". Clearly not the case imho.