What I would want to see: Add in the removed complexity in skills and stats and game systems such as the dialog system.
This is a good place for me to go in!
I agree. I'd like to see more stats and skills, not less. While Perks make everything efficient, etc., most of the charm in old-school RPGs such as Morrowind, or Baldur's Gate, or Arcanum, etc. etc., is that the game offered you a plethora of choices. Maybe not every choice was balanced to a "T", or exactly equal with everything else, but it gave you endless options of how you wanted to build your character and interesting ways to experiment with the given systems. Also, those games genuinely felt different with different builds for good chunks of the game, even Morrowind before you became a demi-god of raw power.
There are so many ways to build/play a character in that game you can still go back today and have a new experience with it.
More things. They should make the UI more immersive. Again, this is an area where they chose functionality and efficiency over feel. The UI in Morrowind is great, but little things like the quest journal looking like a real journal, or in Risen/Gothic how the maps you buy/find are actual paper maps that are drawn, etc., add so much good feel to the game, IMO. And let's be honest, the map in Skyrim, while high-res and cool to look at, isn't going to give you much more information in the vanilla game than a cool looking, beautifully drawn paper map would. The immersive, RPG-style UIs go a long way to making the game feel like a real RPG adventure, rather than some clinical piece of software that aims at maximum efficiency. The Skyrim Perk Chart is actually not a terrible thing in this regard.
What not to do: Don't make it an overly "cinematic experience". Keep the sandbox vibe where the player can craft their own stories with the given tools. Keep any "cutscenes" directly in the game engine and DO NOT add any movie cutscenes to the game. Don't rush the main story. Make it like Morrowind where the player is urged to get stronger and get lost in the world before attempting to start the main quest work in the game. Keep it a laid-back feel for most of the game. While slaying dragons or closing an Oblivion gate at level 1 or 2 is "exciting" at first, this actually cheapens the experience in the long run because dragons are seen as rats, basically. If you build the experience up for hours and then unleash a dragon on the player, while making them rarer overall, it has a much greater effect.
I think just do those things and I'll be cool. Either way the next game will be a must-play for me. I don't really expect them to go back to the old ways, but I can hope and dream. Maybe some other developer takes ideas from their older games and runs with it. I will just enjoy the next game for what it is just like I enjoyed Skyrim (which was "dumbed down" from Oblivion, etc. etc.). Skyrim for its faults, just like Oblivion and Morrowind before it, was a great game to play and just have fun with for countless hours. Not to mention the modding scene, which whew boy! You could spend more hours tweaking and playing with mods then playing the actual game!