No, don't do the Dovahkiin again, for Pete's sake. The shouting/dragon souls thing was fine, even kind of neat at points, but a) it was very much tied into the specific story that
Skyrim wanted to tell, and b) it was entirely pulled out of Bethesda's nether regions, just like the Nerevarine of
Morrowind. I'm sure they can come up with something similarly interesting for the next game, but tying themselves down to the previous game would not be a positive choice.
Personally, I'd be thrilled if they did something with Elsweyr, the homeland of the Khajit, but I'd not hold my breath. (C'mon, a desert full of purring, stealthy libertines? You know you want that as your playground.)
As I work on my second playthrough of
Skyrim, I find myself wishing more and more for more intense testing and fleshing-out of mechanics and plotlines, even if it comes at the cost of a smaller map and less things to do. Playing as a dual-wielding swordswoman with ridiculous levels of Enchantment and Smithing skills worked really well; playing as a more magic-centered character, while it has its perks, really highlights how poorly certain things were considered. The wards and the magearmor mechanic in particular are a bad joke; it's like every magician in the world has nightmares about that first arrow in the neck before they get their defenses up, or worse, the knockdown attack that makes their entire repertoire meaningless. Really, for all the poisons and endurance and magicka draining and intricate patterns of strategy one could use to beat an opponent, nothing-
nothing- beats hitting them hard, fast, and often until they die. They block? Harder, faster, and more often. They use wards? That will slow you down for about three seconds. Summoned or reanimated minions? Ignore them, aim for the summoner. Multiple opponents? Sneak attack them until there's few enough left that you can hit them hard, fast, and often without getting your rear end cut off.
Alchemy is kind of fun, but it's ridiculous that in a game where nearly every town has an alchemist there's so little information available about what reagants
do. I cannot believe that every shop owner got their start wandering around the countryside eating giants' toes and deadly nightshade. Surely someone writes these things
down? In a way other than two ingredients on a scrap of paper? Similarly, it's ridiculous that you can't start gleaning extra effects from all that sampling until you have
50 fricking points of Alchemy skill- this should be the
first perk on the tree. By the point you're that invested, seeking the ingredients you need should be the priority, not nibbling on weird things you found floating in rivers.
And
lockpicking? F@#$ me, did
anyone actually waste their hard-earned perks on making it easier not to break widely available tools that cost about seven gold a pop? For the possible future investment in getting more gold and treasure, by which point it will be irrelevant? Some things should just come from skill levels, not investing those few and invaluable perks.
...Sorry, I can rant on about Skyrim at length (clearly). And a good part of that is how enjoyable the game is, and how that makes some of the flaws stick out so baldly.
For the TL

R crowd, my most salient points: don't re-use the dovahkiin, go somewhere interesting, focus on quality/testing over quantity.