Personally, and this is just my opinion and with a pvp bias, I would rather have a burst question than one asking about an execute. I feel that in pvp, having burst is a little more robust than having an execute. You can still make a great class without the execute. For example, arsenal mercs and lightning sorcs, if you're slow to react, will hit for like 10k heetseekers and 9k thundering blasts. Whereas if you give an execute to Tactics and Assault and change nothing else, they might be like annihilation maraders with steady damage + an execute.
The execute might help out pve a little more, though, since vanguards/powertechs would see a dps increase in execute phases of bass battles.