There are some concerns right now I have for the Greased Lightning rework, but ultimately I am grateful they're doing SOMETHING after sleeping on it for so long.
The rework means that a huge number of skills will potentially be adjusted: Tornado Kick, Six Sided Star, Riddle of Earth, Form Shift, Anatman, Perfect Balance, etc. Are all moves that effect GL, and therefore are potentially targets for adjustments to coincide with the new GL. I don't expect full reworks of these moves obviously (since it's been implied that a few will stay mostly the same such as PB and Form Shift), but it's pretty evident that some will have to be changed, such as TK.
Either way, the decreased Perfect Balance cooldown should be a net DPS gain. It's more mind numbing Bootshine spam, sure, but it's more damage nonetheless. Anything less than 2 minutes will make it infinitely easier to line up with Riddle of Fire and Brotherhood. Even better if it's been reduced to 90 seconds.