I loved Oblivion. A lot of people don't care for it but I think it ruled at the time.
Morrowind is, without a doubt, the superior game
should ended right there
Honestly, what I think of most from Morrowind-->Oblivion is that point in Morrowind where you do (as I recall it) a loop of enchanting stuff that increases your potion-making, potion-making for better enchanting ability, etc., until you get to this sudden point where you can make insanely-powerful uber-enchanted stuff.
Now frankly, sounds dumb, and terribly stupid, and pointless. Sounds kind of game-breaking, really.
The thing was,
it wasn't un-fun at all. It was the most entertainment you could have in a game at the time.
You just make a set of equipment with insane Athletics/Agility/Strength/Acrobatics and whatever else, and then you could jump into the air and fly around like Superman, and the game would draw pretty much everything for you as you saw the whole world (very relevant to this 8k/file-size squabbling), and you'd just explore the world in a way you could in so few other games...
Instead I get to Oblivion, and not only did they have the most abysmal level-up system that had
everything in the world level with you to the point that it feels like there's zero progress in the "getting more powerful" sense of character development -- possibly the worst thing you could ever do to a game like that -- they removed all the
fun game-breaking things like the aforementioned enchant looping in Morrowind, but kept around the most braindead yet easy-to-acquire shit like 100% chameleon which just causes each and every NPC to stop interacting with you, including enemies, which would just literally stop moving as you killed them.
Arguably Oblivion was better in 95% of ways, but the 5% of ways in which it was worse were WAY too painful. I'm still ragey about that game to this day. In a sense Skyrim recovered from that by at least not having the leveling system be abysmal. Whoever did the Oblivion thing should be thrown off a cliff.