Yes, it makes no sense. Goths are a Ruh civ that is at it’s strongest in Castle Age. Pushing their bonii to Imp is just going to make them bad and unplayable at a competitive level.
The only way to fix that would be to give them Plate armor (Gothic Plate, ironically), but that would also make them less unique, and just a buffed up Generic Super Infantry civ.
They should give back the 35% Feudal Inf cost reduction, give Plate Barding armour so Goths get at least FU Hussars on lategame, where they suffer the most, and modify the pop bonus from +10 to +10%.