1) Yes. I started literally on day one of release, and by the time the mem was rampant I'd heard it twice. I had to go around deliberately talking to gaurds to see how common it might be. But I'd love to see a DLC adding more guard talk mocking this.
2) While in theory a quest chain may only have a few stages (the main Companions one is about six IIRC), each stage can be a couple of hours long, and there are almost always official side-chains as well. The TG questline alone is longer than many FPSs. Sure, I'd like even longer, but I don't think they are too short.
3) I've had about three game-killing bugs in 460 hours of play. At least two broke the MQ in the sense that the plot got stuck (in one case a cut-scene wouldn't finish, but kept looping). But old saves got me out at as loss of no more than about fifteen minutes play. The game auto-saves a lot, but offical advice to manual save a bit would help. I also had a texture and CTD issue that turned out to be me trying to run the graphics too high. Other than that, little things, often amusing (I'm still trying to work out if the falling dead dragons are a bug or a feature). Having done my own mods, and seeing the complexity of what Beth are up to in the background, bug-free is probably impossible before release. And trying to distinguish which bugs are common and repeatable from the odd thing on odd computers, is probably nealry as hard.
4) I find play plenty hard enough. If you really want a chanllenge, there are plenty of ways of gimping your character: try never using a perk for instance. I'd like a bit finer adjustment on the slider rather than just five fixed settings, but I can live with it.
5) Well, yes, but almost unavoidably. Again, try making your own dungeons, ad see how much work is involved. Now try that with a new set of textures and new shapes each time (both of which will have to be bug-fixed each time before use), and you've multiplied by 11. But within the limited number of basic sets available in the CK, the amount of variation is astonishing. And personally I'd like to see a DLC set entriely inside Dwemer ruins.

