I agree with much of what you say, though you sound more "disappointed" by Skyrim than I was(!). The advances in how skills & levels grow were brilliant, IMO - though you have a point the "stories" were not all they might have been (esp, as you say, the Dark Brotherhood line).
I don't mind them having only specific houses for sale, I think it's fine to have only set player-ownable houses. What I do think would be nifty is having some choices in outfitting them. Instead of the preset rooms, maybe you could choose to an Alchemy lab or Enchanter - or more bookcases or weapon-mounts or mannequins... or chests!
More choices of what to put IN the house might make it having to be that house less confining(?).
You lose me a bit on staves. They're enchanted weapons. You don't get any skill-boosts for using a fire-sword, why should you for a flame-staff? The magic is in the weapon, it's none of your doing. One option might be to have a staff improve your spells by 20 percent or so(?) - using them would cost you magicka, but you could cast any spell you know through the staff... no enchantment on the staff itself (to wear off) - it would just be an extension of "you" (and level with you)...?
In general terms, I'd like to see them dare a game with even less (or no??) Main Quest at all...! I don't care for games that lead you by the nose, and one thing I ~loved~ about Oblivion was that if you just don't go to Kvatch, the Gates never start opening all over the place - and you can have a good "life" ignoring that whole thing!
To me, it comes down to that "chosen one" beginning: in Skyrim (as in Morrowind) you are inescapably The One; in Oblivion, you're just a prisoner. Sure, the Emperor saw you in his dreams, but you're not really obliged or anything...!
I think the "Main Quest" should be "down-sized" into something more like a guild or faction option. The Elder Scrolls games are uniquely best for providing that "sandbox" of free-will... and Skyrim was maybe a bit of a step-back in that.
My only complaint is that they do "push" us a tad... you begin the Dragonborn, and seeing a dragon, so you're thrust on that path - and a lot of the faction-quests seem to overlap: that is, finishing one ~assigns~ you another in the same dialogue-blurb. I'd prefer having to go ask before I am "assigned" quests... I'm playing a game for fun - I don't want a huge To-Do List in my spare time too!
Skyrim does go a long way to "organic" play and does allow some open-ended options (Max Von Sydow wants me to kill the friendly dragon, Christopher Plummer says no... and Plummer did win the Oscar this year...?) - but you make good case for an even more free-ranging set of warring-factions. D-Bros vs Morag would a be very cool story line!
I'd have it come late: after you've done a few (ahem) hits, you become aware there's another murder-for-hire bunch out there. Being sent after Morags could be a late mission - or, it could come the other way... after you've joined the DB, maybe a random chance begins that Morags come after YOU!
