Zhaleskra
Adventurer
Con's:
-Complex:
Freedom is hard. Everything in Class-less systems is more complex, because it has to be more compatible. Combat rules have thousands of exceptions noted, every skill has complex effects if used in collaboration with other, certain things don't work together, this has to be noted and explained. (Somewhat exaggerated)
-Harder to understand
Whereas DnD you only need a basic understanding of the rules, and a bit better understanding of your Class, Classless systems require you to know something about everything you chose and things relate to those chosen things. Combine this with a very complex system (see above) and it's no wonder new players just give up when I force them to read GURPS.
All above was meant to be unbiased, I'm not sure I succeeded. If I missed things (which I surely did) please tell me.
I think you missed. Probably because the only classless systems you appear to have dealt with have been super complex. While World Tree doesn't really have "combat exceptions", it technically has three combat systems. All the various uses of magic use the same rules, after their own peculiarities. Then again, that is only one example.