Eh, them keeping things under wraps is what they do. They don't overdo demos...that's just what Bethesda does. For them to actually do a press conference for E3, which they NEVER had done, does more to instill confidence than give alarm. And most likely the closed audience thing is probably to build suspense and tension to boost sales, more than anything else.
Their games are buggy, everyone knows it. No big secret...but not game breakingly so. It is definitely nothing to be alarmed about. It's just how they do things. They did the same for the Skyrim launch. It may have been buggy or whatever, but it was more than playable for me on 360 and PC and I never encountered anything game breaking ("Blood on the Ice" was my biggest issue, and eventually it even triggered). And it definitely was not over shown to the public before release. Same thing for FO4.
I'm not alarmed in the least. The overall game will be a sufficient sandbox to do virtually whatever we want. That also is what Bethesda does.
The only thing I'm still just a bit on edge about, if anything, is if I'm gong to be able to reload ammo or craft ingestibles...all maybe removed from the line-up just so people can play Minecraft. 