I get the thread people are grasping at, but as a caster that solo'd a lot of the way to 65 and a lot of my AAs as a fresh 65 (since soloing is the only situation where there is any strain of reliability in the number of casts it takes to kill a mob) I think its a stretch.
First off, if a mob takes 3 nukes to cast, and you are getting reduced by 10%, there is only a 30% chance that the new system would cause you to cast an extra spell. 70% of the time, the mobs hp would be low enough that you would *always* kill it in 3 nukes. This actually brings up a weird situation where the change actually does make people stronger, but this situation is pretty rare.
There aren't many points in the game where you can kill a mob for exp with 3 nukes. There are places where it happens, right at a spell level, killing a low level mob. More often though, its going to take a lot more than 3 nukes, and maybe I have rose colored glasses, but as a nub wizard I remember getting resisted more like 15-20% of the time on your average non resistant mob. Resists were common and expected when kiting for exp.
I'm sure there is someone somewhere that fits the mold you are describing, and happens to hit that mob hp sweetspot where suddenly they have to nuke an extra time per cast, but this is an rare situation, and not (imo) a good justification to revoke a really great improvement for the server that most players appreciate.