Where did I mention Fireballing when solo? I didn't.
You said that warriors and archers don't know how to play properly to support your Thunder, thus reducing your efficiency.
My argument was that Fireball is greatly superior to Thunder in party play. Therefore, it's illogical to say people should learn to cope with Thunder, when a good mage can just switch to the party-friendly Fireball if the party can't work together effectively.
Your counter argument is that Thunder is better for solo? Irrelevant.
Most people think that Thunder is the end all of advanced magic - Ice Spear is weak and Fireball is too slow without cheating one-change - which is why I tossed in the overrated comment.
Also, what party missions are you running? Because those numbers are nowhere close to something like Shadow Wizard. In a five wave Shadow Wizard, I usually have time for 2 Fireballs. Average party size = 6 people
250MP = 16% Exp for Fireball
550MP = 100% Exp for Thunder, assuming you can actually kill all 7-9 mobs with one shot, each time. More likely, it'll cost you at least 1100MP, assuming the mobs hi die in one Thunder, and you hit the entire wave in two shots.
Yea. Good luck with that. I don't even pull out my wands unless I'm in some serious dungeon. Melee is much faster and cheaper than magic in things such as Ciar Advance, which is what you seem to base your numbers on. If you've ever ran Shadow Wizard Hard with a good party, then you should know that solo exp can't even compare.