The bow's Power enchantment should do +1.5 damage per level instead of increasing damage by 25% per level

In 1.9, Sharpness was reduced from adding +1.25 damage per level to +0.5 damage per level, and the Strength effect was changed from +130% to +3 hp. However, bows remain unchanged and increase damage by 25% per level (50% for level 1).

A fully charged Power I bow does 5 more damage than an unenchanted bow, and a Power V bow does over twice the damage (25 vs 10, enough to instakill someone with full Leather armor). Since the bonus is multiplicative, it gets worse if you consider modded bows with higher base damages (the same problem that Strength used to have with swords).

My suggestion is to lower Power's damage bonus and have it be absolute instead of multiplying the bow's base damage, similar to how Sharpness and Strength now work. Each level would add 1.5 or 2 damage to a fully charged bow.