Besides Mercer, this set would have been great provided if the rest of the helmets come off the figures. At lease make these Vipers stick out from the single and comic pack ones. I feel really burned right now by Hasbro considering I already have 10 single pack Vipers. Same goes for the Crimson Guards. It seems that there is no point army building single pack figures as Hasbro will make a 5 pack down the road. I suspect the B.A.T.s will follow the same route.
We can only hope that the bats come out, and without the paint wipes. ;-)
The Mercer helmet isn't a removable helmet I believe, only an alternate head, like the one that came with Flint.
When all is said and done, they will rerelease anything that will sell. I think that the Viper with fixed hands will come out in another army builder pack. Whos to say what else will be in it, but they aren't going to make a mold change like that for one packaged release.
I'm not entirely convinced that we won't get fixed wrists in this pack. If we don't I'll pass and wait until H packages them some other way.