What else is there except how they were implemented, though?
People want Cliff Racers to be cut from every future TES game, and seem happy that they weren't included in Oblivion. Implementation in past games has nothing to do with what you want in the next game. There must be a problem with actual Cliff Racers, not the implementation of them, for people to want them to not be included in future games. It's an obvious fact that Bethesda are going to learn from thier mistakes and fix them. I mean, they learned that NPC's standing around all day and night wasn't the best decision, so they fixed it in Oblivion.
For example, voice acting. I'm one of the ones who don't want it. Not because it was poorly implemented in Oblivion, I mean, they could easily record better voices, but because it fills up so much disc space. And don't bother arguing with me on the topic, I'm putting across a point about Cliff Racers, it has nothing to do with it, and I'm just going to ignore you.
You answered your own question. People hate Cliffracers because they were horribly implemented in Morrowind. And until Bethesda puts a flying creature in a game that is implemented much better, then people are going to keep hating them. If TES V has Cliffracers but their AI is astounding, people will stop hating on them. But until then, people will remember how they were implemented in Morrowind and they will base their opinions on that.
No, I'm sorry, I don't buy it. The implementation of Cliff Racers in Morrowind is no reason to ban them from future games. A lot of us think Bandits where poorly implemented in Oblivion. I wouldn't expect them to be cut from TESV.