Skillchain Damage is fine i think, They basically add 50% more Damage, or Double your damage when you do one, They're already a very powerful thing to have.

I think a great boost would be: (outside of my previous post)

Increase the window in which Skillchains can be performed. I think this'll help the "I don't wanna store TP for SC" thing. Increase the window for Skillchains to ~15 Seconds. This will allow more free-usage of Skillchains without people blowing WS-Phase DMG off by storing TP.

This would help a lot, Perhaps extend the "Magic Burst' window as well.