No, it would make the game easier. If monsters didn't level up with your party you could easily over-level and crush everything. This would be even easier than other FFs because you only need 1000 exp to level up.
The enemies on the ICH are always level 100.
It took that long for you because your Magic stat sucks. Your success rate at drawing is directly related to your Magic. With something decent junctioned to your Mag and Spd you should be able to draw 300 spells in a few minutes (around 1 or 2).