RPG games

Not familiar with this game mode and the description doesn't offer much tbh. You might find something of interest with CRPGs like Pillars of Eternity, Baldur's Gate, Icewind Dale, etc, but since I have no real reference to go by I'm more or less taking shots in the dark. Sorry I couldn't be of more help to you :(.

Not sure if you want something with Warcraft 3's gameplay or the class system you mentioned. But Maple Story, La Tale and Flyff have very fun class systems similiar to what you described.

Try Battle for Wesnoth. It's a tactic game with rpg elements but you can find some campaign made by user similar to the one you descibed.