Can is a poor RB and even poor LB, at least in the games I have seen. He is good in the midfield though and that's where he should be playing for his sake.
Why I like to see him as LB? For obvious reasons. He is not very good playing there and better as midfielder. So playing as LB means not playing in his best position.
Your post doesn't make sense. You've said he is a poor RB and even worse LB from the games you've seen, yet admitting you've only seen one game where he played their previously.
And yeah your second point makes great sense. Can't wait to see Vardy playing as an anchor man at some point, and when are Arsenal finally going to play Mertesacker as a false 9?