To be honest, I'm more confident on the Rickie Lambert signing being more of a success BUT ONLY because I know absolutely nothing about Can. Sure, I've seen the Youtube videos, but even I would look world class in a YouTube compilation video.
I sure as hell hope he's an improvement on Lucas. We won't be able to play Gerrard all the time next season so hopefully Can's defensive capabilities makes him a satisfactory replacement for the captain. Of course, we still keep Lucas as he offers depth for a busy season, but against stronger sides he shouldn't be playing (unless we want him to be given the run around constantly).
But only 20 years old, years of development ahead and for less than £10 million in an inflated market is a good deal that can't go wrong. Fingers crossed he turns out next season to be an absolute steal.