I actually trust this date - for some reason. Maybe it's because it's "11-11-11" and it would be a PR fumble not to stick to it - or maybe it's because the game looks very polished even at this stage.
They have enough resources, that's for sure - and they've done literally nothing but exactly this kind of game for many years now. I think it'll be out in time.
They haven't released a TES demo since Daggerfall (Battlespire, perhaps?) - so that's par for the course.
I don't think it would be that hard to just do a dungeon or something - which would be just fine in terms of demonstrating the vitals - and obviously it's a PR bullshit excuse, but I don't really think I will require a demo for this game. TES has a long history and I've found them steadily improving in most ways - even though they've always sucked in others.
I'll be buying it with reasonable certainty.