If you kick then overhead someone, you aren't holding your swing and you aren't getting a good speed bonus. That's probably the main thing. If you are holding overheads properly and w-keying with any high cut weapon in the middle of a clusterfuck, you will Feel the Power properly.
You aren't going to one shot anyone but a peasant if you are infantry, unless you are playing Strategus and everyone is in shit armor however.
Also, if you want to "play correctly" as a 2hander, you are supposed to killsteal other classes. High powerstrike or high damage weapons are meant to ensure you get the killing blow (on a enemy or teammate) from behind on a shielder who just "skillfully" backpedaled while holding RMB and spamming stabs against a 360 jump spinning awlpike user.
Ironically this is why balanced builds are best for kills as 2hand, you do enough damage to killsteal, remain fast enough to get in position for the killsteal, with enough HP to survive friendly archers, pikers, and cav trying to killsteal you within the first 2 minutes of the round.