Well, there definitely needs to be some kind of rebalance.
But not because of the no epic charm weapon.
The best charm gear totals to 573, the best hardcore gear totals to 580, but the best know-how gear totals to 688.
Which means that charm and hardcore are about equal (hardcore misses out on good body equipment, which has two epic charm items), but know-how has about 100 points more in total.
Now that should be rebalanced.