Hi,
I'll keep it short: this is what I've done for a living. I'll throw in things I've encountered or glanced at.
Jokers
Weakspot Refund:
Even with perfect weakspot accuracy the ammo restoration is a fraction of what Ammo Supply gives, but uses the same amount of joker slots. I would rather pick 3x glow to reduce friendly fire incidents.
Suggestion: Gray joker it with 50% chance, or a rework to 50% chance to add ammo back into the magazine upon weakspot hits -- kind of like an alternative version of Leveredge's unique joker. Rework in this manner would allow for more build variety and create new niches.
Battlemage
Scales incredibly hard on higher difficulty levels, especially when coupled with Wisp. At minimum feels like it should be legendary tier; perhaps a numbers nerf is well justified on a per difficulty level basis.