GotAD now has a progression system called "Feats"!

They can range from basic PvE kill quotas to unique PvP challenges. Once completed, Feats will grant your characters passive upgrades to their stats, as well as the ability to unlock classes if you manage to complete all Feats in a particular part of a class tree. 

Multiplayer PvP playtests still occur Saturday evenings (join the discord for more info), but always-on multiplayer servers and a formal release is very, very soon around the corner.

If you want, check out the browser version here : http://gotad.io/    (Feats and other amenities are client exclusive, though)