Honestly, I think Sneak Attack needs to be automated, not something you activate.
Eh, I think it's essential that we have the option to activate it. Sometimes you might want to sneak attack only on the second (i.e., off-hand) attack. Say you want to finish off a 1 hp enemy right next to you and then attack a 10hp enemy behind them. I don't want to waste my sneak attack on the 1hp enemy.
