A small buff idea for Kogmaw

So, was talking with my friends and after reading a few things from RiotRepertoirs thread, and after playing plenty of lately; why not make it so that his W works similarly to s, in the sense that if it hits an enemy CHAMPION it extends the duration by X amount of seconds. But it only works if he hits a champion, as to not allow him to get say, 10 seconds of turret wrecking power, but makes him a bit more dangerous in a teamfight.