Quote Originally Posted by ZiraZ View Post
there is absolutely no drawbacks from doing so with the main weaponskill combos.
You have two enemies, one is at one HP, the other is full. You are at the end of your combo. You could use the combo finisher on the damaged mob, wasting potency or you could reset by going to the combo starter which would allow you to start attacking the second mob with the higher damage combo 2 button. DPS gained.

This is a niche situation, but there are drawbacks to forced combos. They are less interesting to play in my opinion and they take away optimization options.