A healer style cleric who previously had +80 positive spell power is easily over +120 now while healing bards are pushing 90ish.
Giving a bonus to bards and then giving a bigger bonus to other classes continues to give bards less relative effectiveness.
Bards don't need less spell power than other classes. They are already restricted in the spell lists and by smaller SP pools. Additional class based spell power adjustments just compound the game mechanics against them.
Giving bards a big bonus to sonic spell power doesn't do them any good until sonic spell power applies to something where the damage is realistic to other spells. What they need is spell power that works towards the spells they are most frequently using and that would be healing, of which there are 7 spells on the bard list as opposed to 4 sonic spells.
If I really wanted a jack-of-all-trades character it would be a wizard 18 / rogue 2 using a staff for melee (and acrobat) and scroll healing the party. That covers traps skills, spell casting, healing, some melee options, and stronger spell casting options.
If I'm making a bard it's for buffs and healing, and sometimes CC.
The devs need to take step back and look at why they are restricting bards so much and seem to be missing the benefits they are stacking on to other classes.