Yeah, I found a Rank 9 damage enchantment at level 20, shortly before the Battle Tower boss fight. I've NEVER had that boss fight end that fast and easily before. Same story with Lord John and Lady Kara, it took mere seconds to kill them. Leaving high rank enchantments intact isn't solving anything.
The old Ego Draconis enchantment system wasn't very good either. It made Rank 10 enchantments COMPLETELY and TOTALLY pointless, because it gave exactly 3 more damage than Rank 9.
Before the patch I was hoping the enchantments could be cut in half:
Rank 1 = +5 damage
Rank 2 = +10 damage
...
Rank 8 = +40 damage
Rank 9 = +45 damage
Rank 10 = +60 damage
They'd still be worth using at the time you found them, but they wouldn't get super-overpowering.