User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-186.145.130.238-20120221145408/@comment-70.54.115.173-20120222030601

Monster Hunter games haven't traditionally pushed space limitations; the PSP games only went barely over half of the maximum size of the UMD if I recall.

It's more about the amount of work that goes into it. If they didn't bother adjusting armor skills, damage, etc. they'd still have to adjust all of the models and animations to fit the same standard.