Clumsiness is fine, but it needs positive or interesting effects that add to the gameplay variety rather than just nerfing basic controls. For example warioland series has a lot of different effects from falling, rolling or being hit by enemies.
In the end the core platforming should be predictable to the player. I just read about and tested the stamina system and it doesn't feel like it should be like that. The stamina information is visible diegetically on the wings, but those aren't shown before you execute the jump. In platforming sections it just adds wait time which I need to guess each time. It also funnels me down a loop of: basic jump is really low -> use flight all the time -> use up stamina -> basic jump is even lower. The worst part is the jump not executing on sprint startup which is required to even do the jump, but alone does nothing other than reduce friction. It's possible to account for all of that with distinct animations, but I wouldn't recommend that regardless.
The better way would be not using stamina for the basic jump in any way, and making it tight and controllable, but making the extended flight be stamina heavy with little control (like it is now) and landing penalty because it's a high commitment move.