Improved Improvisation halves the non-proficiency penalty with weapons, while Quick Learner reduces it by 2 after your first attack.
Would these two feats stack, and if so, in what order?
Base 4 / 2(II) = 2 - 2 (QL) = 0, free effective proficiency in all weapons.
OR
Base 4 - 2(QL) = 2 / 2(II) = 1, -1 non-proficiency penalty
OR
Nonstacking, 2 either way.