DND_Reborn
The High Aldwin
For Druids and Monks IIRC you had to challenge to reach higher levels around 8th to 13th. I'd have to grab my 1E PHB to be certain.Wait, didn't AD&D tie level advancement to something class related? I remember seeing stuff like "if you want to level up as a druid you have to go to your grove and challenge someone for their position", and that looked pretty awesome.
Glad that works for you, but feats increase power creep too much IMO. We do allow skills, as well as the tools and languages normally offered, during downtime.Edit: oh btw I came up with my own answer to exactly that question of how to give them features in between levels, and it's offering feats through NPC trainers. Getting a feat isn't as powerful as a level and there are also many juicy looking feats in terms of RP that don't look all that crazy mechanically, you get to choose which ones you offer after all.