depends on at what point we receive these.
getting magic plus early unbalances the magic/phys even more.
the OCD in me will hate having characters at different levels due to exp plus, but i suppose having tifa several levels above everyone else will balance that out.
and is it possible to turn mug into an attack replacing command? always seemed like a better way to have it than having to keep low level steal materia.
Most of the Plus won't drop until very late in the game, by which point physical attacks will be able to more than hold their own with Ultimate Weapons/advanced Limits backing them up.
Another way of looking at EXP Plus (and how I tend to use it) is catching up other characters to Cloud's level, as he invariably tends to end up higher level due to getting full EXP for the majority of the game. If you got your hands on a couple, then you could manage them to keep your party's levels much more in line with each other.
I think it's possible to separate Mug and Steal, but it's an .EXE hack and it had some problems if I remember right. Though if Slash-All/Double-Cut can replace Attack with no problems then maybe Steal/Mug can do it too? The risk would be that Steal would also replace Attack, which means separating the commands onto different Materia.
Found some bugs. One is on the Carry Armor type boss in the dark cave. If you use Quad Ultima + Ultima MP Absorb the game hangs. Also, after I get the sector 5 key, I'm teleported to the north cave and after the dialog the game hangs. I can't get passed that point.
The first is a problem with the game's engine; it occurs whenever a Quad-Cast of Ultima + Absorb is used against any enemy with multiple parts:
http://finalfantasy.wikia.com/wiki/Quadra_Magic_Ultima_glitchAnd despite what the Wiki says, I can confirm that it does occur against against Jenova Synthesis :l
https://youtu.be/C1U3OvCojBA?t=2m35sAs for the second problem, that was (hopefully) addressed in the flevel hotfix patch. Try applying that and seeing if it still occurs, unless you're on the 7H version in which case let me know.