If you look at the enchantments list, none of the things there are as good as quantum armor or electric tools. Some of the items are real handy - such as a silk touch pick or one that causes extra drops sometimes - but nothing gamebreaking so long as you can't enchant that quantum armor or that rechargable mining drill. You can get water breathing on a magic helmet, or you can get water breathing AND partial immunity to all damage AND automatic feeding AND automatic poison antidote AND rechargability on a quantum helmet. You can get resistance to explosions or lava on a magic piece of armor, or get immunity to ALL damage on quantum armor.
So this is easy to fix. Add an isenchantable hook to Forge and make it so none of the electric IC2 items are enchantable. It probably would work fine if the Bronze items could be enchanted...make them equal in tier to iron items with less durability. That way, players would still be able to spend their experience on stuff, the game wouldn't crash, and everyone would be happy.