Oblivion is a lot better than Morrowind in my opinion. Morrowind is good for its time, but having to walk extremely slowly everywhere you go with no fast travel gets boring in about 10 minutes.
Plus, I generally liked Oblivion better even without that issue, minus the gear scaling, bandits running around in full elven armor was annoying.
Morrowind is about twice as big as Oblivion though. There are 199 quests in Oblivion, Morrowind has 376 without expansions. Plus it doesn't have these pesky Oblivion gates that pop up while you're doing something else. I really hated that about Oblivion. There were 60 of them and they were all basically the same.