I consider any game that requires me to go out of my way and grind to level up completely flawed. I stop playing it shortly after, I want to have fun when playing a game and grinding isn't fun.
I dont get why, but I actually like to grind. It's weird, but don't judge me!!! Maybe because it's a part of the game in itself, or maybe because I am so obsessed by being as high a level in a game as possible. Or maybe its because I just like killing stuff. But I enjoy it.
To tell the truth, I actually tried to avoid some battles, but still got up in the mid 50's before the Lavos battle.
That, and I entered the Black Omen, then left before the Elder Lavos Spawn fight to go 2300 AD to revive Chrono. The sidequests involving Ozzie's fort, the rainbow shell, and the Ruined Castle (where Cyrus' ghost resides) all helped in preparation for Lavos.
But the Retinite in the desert destroyed me good, when I chose to fight it early. Destroying the core is bad for your health.
I think I enjoyed the the Ozzie's Fort sidequest the most. Going by memory, you attack the buttons and end up falling down to the previous floor. What follows? Ozzie gets defeated by the paws of a cat!
I couldn't even put the game down for the first two weeks of the semester, completing it with a log of 27 hours.