I think an interesting extra downside would be:
If, during "pre-slashes" with the sword out, you decide to enter combo mode with the left click, Trunks tosses his sword up in the air. If he breaks the combo (deals the last hit), he leans to the side and the sword falls into the scabbard (as he does when he first arrives on the scene after whupping Frieza and such). If the opponent breaks the combo, the sword misses and either: hits him for added damage, or just falls to the ground where he needs to pick it up again.