As much as having our cake and eating it too sounds nice, it's just not plausible.
Personality was useless in Oblivion because Oblivion had zero dialogue substance, and because everyone was filled with happy sunshine dust in Oblivion. Scantly anyone hated you and if they did, it was reflected in greeting only. Whereas in Morrowind, personality actually meant something, as you were constantly aware of how much practically everyone one the island thought you were scum without it.
You could have both honestly, there were actually a lot of "deep" characters as the games progressed. In Fallout 3 there was the girl with the Nuka-Cola fixation, and the guy who was in the place with her just wanted to get in her pants. It was a lot better than a lot of Oblivion's characters who wandered around and said "I'm a hunter" but they never hunted, or never did anything other than wander around a town.
It would take more time, but Bethesda could easily afford to spend time on the characters too, you can sort-of see as the games progressed how each person gained their own personality, and strayed away from saying their own things. Asking about the City the character inhabited in Oblivion actually gave you a quick glimpse into their life. In Fallout 3, it was more of an action focused game, however, little kids each had their own personalities and stories, old people could tell you about the "good old days", travelers could tell you about things they went through, etc.
On the path they're taking and the fact that TES is known to be less focused on "gunning down" everybody, I'd say that they've got to open something up and develop on it more. All they have to do is add certain things to characters, like habits, back-stories, motives, likes, and dislikes, and people with a high personality skill can talk to people about more.
I'm sure that combat, spells, and the in-game world will be vastly improved, but they seem to have been developing characters as they go on too.
:) I have hope, I think "personality" will be better in the next game. Bethesda's gotta keep up with its competitors.