Thats why its extremely slow, and if parried it would disarm or make the attacker vulnerable to combos, among others. i was also thinking that the move can be negated by an attack from the opponent.
Well, a move like this would need penalties more severe than that to avoid spammage. Probably the best option would be to have the effects of getting parried based on your opponents DP meter when you tried it. If your opponent was almost full of DP an you got parried or hit while in the swing, the effects should be almost lethal on you. This would have lessoning effects on you the lower your opponents DP is. However, I have a feeling that razors going to think this is not a needed feature at all. This would be a huge change to the saber system and alot of people don't want to see big changes to it.