Haste
It's haste, what really needs said here? Everyone loves it, and it should be used on everyone. I've seen a few people want it to be scaled with enhancing skill, and personally I'm against it. If they did, it'd advocate whm/sch more for a stronger potency haste.
Proposed change: Change it to 5% haste, scales to 20% at 500 skill and watch everyone cry.
So you think it is ok that a level 48 (or less /WHM) job should be able to cast haste for full effect? The same potency as a job at level 99 can do?

It is an easy fix, anything over 200 skill increases the potency of the spell, this means that if someone casts it in 500 skill it is actually distinctly better than the BRD/RDM casting it. (the fact BRD/RDM can cap magic haste on its own is pretty retarded.)

Or they can just make it potency based the entire way, 100 Skill per 5% haste, caps at 25%.

(or they could just give RDM and WHM Haste 2 @ 25% and call it a day.)