LogFAQs > #966174991

It's actually pretty important to note that difficulty balancing is WILDLY different between P5 and P5R.

Mania mode now gives you 1.2x exp and money instead of 0.4x exp and money. (Both versions give x3 weakness/technical damage on Mania.)
Player damage in Mania mode is now 65% instead of 80%.
Technicals are OP in Royal and can be made to have 100% knockdown chance after a while.
Baton Pass is also OP in Royal and scales damage even harder
Player movesets generally buffed (e.g. Ann gets Dormina almost immediately which just kind of wins the first half the game)
Specific moves, most notably Swift Strike, nerfed
SP/sustain is significantly easier without Invigorate 3 (Death confidant accessories)
Most bosses and minibosses have different movesets/AI/events during their fights, usually in the direction of making them easier and more telegraphed.

Most people would say that P5R is pretty significantly easier than P5 on higher difficulties, especially Mania, with the exception of the "corporate" palace's boss being kind of insane on Hard (but trivial on Mania) in the Royal version.