good things about oblivion: the combat system, voices, npc schedules, casting spells in combat mode...
bad things about oblivion: no dropping of quest items [honestly, if i lose the great welkynd stone, i deserve to spend the rest of my oblivion days looking for it. access denied to silorn, sancre tor, the arcane university, geez, i just want to see what's there without having to deal with j'skarr. too many other things to list here...
but the worst, to me, is no sense of grandeur, no panorama. the entire continent of tamriel is saved from Oblivion [horrors!!] and some weeks later, i walk in to a warehouse, not even a warehouse, a storage area, and i pick up my armor. i could hear the guards snickering on the way out, 'sucker.'
good things about morrowind: a magnificent storyline WITH a sense of grandeur and a certain bittersweet quality, that beats anything i have ever read in a novel [and i read -- a lot] and i'm not just talking about the main quest, also the houses, the morag tong v. the cammona tong, solstheim, tribunal.... a druggie supervisor, a quirky man-god, a prissy supervillain, an incredible wise woman of the ashlands, werewolves, the bipoar blade...
bad things about morrowind: gee, can't think of any offhand -- oh, yeah, cliff racers.
i feel that the hoodoos, guroos and suits at bethesda [azura bless 'em] are not going to abandon the good things about oblivion, so make them better, and by that i don't mean more candy.
here are some examples:
beggars are people too. let them be a useful source of information for everything that goes on in tamriel and oh, hey, now you can get rid of those map markers: 'heronymus lex, that old windbag, he goes to lunch every day, at 12:30 at the bloated float.'
[on a side note, everytime you give them a hand out let it count for .00001 fame point, or something. make use of those voices and that time.]
again, with voices and dialogue, alternative choices in all questlines, good choices for the good guys in the thieves guild, bad choices for the bad guys in the main quest. with a way to continue and complete the quest, of course. this calls for some inventiveness, but hey, i have faith in bethesda *grin, with accompanying innocent look*.
delay the main quest until level 10, or until you have gotten to a certain level in a guild, or whatever. make it a requirement to have some fame points before your combat worthiness to undertake the main quest, is recognized. make a way for bad guy players to become fame worthy in spite of their chosen occupation. which leads us to...
every quest should be begun by an npc, not the player, like the pale pass quest in bruma or the order of the virtuous blood in IC. every quest.
last thing about voices, do not, i repeat, do not lose lynda carter, even at the expense of losing sean bean, et. al.
lastly, bring back the houses and the morag tong and malacath bless 'em, those lovable cammona tong thugs...
my fantasy for TESV: combine tamriel and morrowind: the prequel. pick an earlier era than that of either game, show how it all got started the guilds, the houses, apolgies to reguard, daggerfall and arena.
i think i'm beginning to ramble....