The process of learn will be harder, but also the difficulty will be based on luck. If you have luck, and the boss doesn't use often a specific wipe mechanic, you're good, but you have also de possibility of have just the opposite, the boss spamming that skills. Random mechanics cannot work in a game of this type. Even on turn base Final Fantasy games, the bosses are scripted in majority. Full random things are uncontrollable, hard to balances and the success is heavily based on luck.

Think on a simple mechanic as Emptiness of V4 Savage. If I remember well, it have 64 possible combinations, some of them are very tricky and can cause a wipe, but others are so simple that you don't need to even move. No think in all like this for an entire fight.

A lot of people complains about how predictable are the battle once you learn it, but it is the way this game works. Random things are ok in low quantity, such as V3 Halicarnassus four jump variants (Blue tile, Library, brambles and clock), which uses randomly. Yes, it is random, but still, you know they will use one of this four in a specific moment.