It wouldn't surprise me if that sort of thing is more common; the KOL version is the only one I'm familiar with, but I think it works very well there and it fits with the ease of use of the game engine. You can't really multiclass in KOL, though you can switch between classes under certain conditions and you can keep skills from more than one class. But your main stat is based on whichever preference your current class uses.
Easily my
least favorite stat system would be AdventureQuest's. I like the game engine in many respects, but I hate their stat system. You have the usual six RPG stats with a max of 200 points possible in each stat. These affect not only individual facets of your character but also things related to class training, since AQ has an open class system (you can train in just about any classes you want, and wearing class armor lets you access specific abilities).
You can improve your stats with NPC trainers, but the catch is that they charge money for said training as well as stat points, which are only awarded each time you gain a level. The number of points you can get from training is fixed but the cost tends to scale according to your level and/or the existing stat, which means you're basically paying more each time for the same base increase. At the higher levels, where it takes a long time to level up even with regular play, you can easily have enough money but no stat points to train with. Worse, and endlessly frustrating to me, the stats related to class quests are tied into the game's RNG. If you're training to be a fighter, the necessary stat will naturally be STR. You'll have to quest for several days and defeat all opponents, with not quite enough rests for every single day.
Before you fight the last battle, which determines whether you can gain a class level, you have to pass the RNG based on your existing stat. If you fail the random result, which happens quite often unfortunately, you automatically fail the quest and have restart it again. So you could be strong enough to defeat the necessary enemies, but still fail because the RNG hates you.
They did improve the stat system considerably with MechQuest though, whose engine is an improved version of the AQ one. The RNG is less frustrating because it occurs more frequently, thereby making the overall results less blindingly bad, and in some cases you can actually use items that increase your chance of passing a specific RNG roll. And the overall stats are more balanced and more easily trainable.