Yeah, hey Ez, when are we gonna get another champ that can have solid alternate builds like ap/ad kog or ap/ad ezreal or ap/ad master yi or ap/ad sion or... (etc., you get the idea right)?
Personally, I really enjoy knowing that if I play champ A and don't do well with build A then I can try build B and see if that works better for me.
Now, I don't mean something dumb like, tanky dps/pure tank, cuz honestly the only difference is the amount of dmg you are doing, your role hasn't really changed much if you build more offensively or more defensively. Or something like varus, he is ad carry, he has decent ap scaling, but he will never be a suitable mage because most of his dmg relies on his short aa range to get stacks up on his passive. And any competent team will melt a mage's face off if it were to get that close.