You can't really categorize heroes like that. I've seen a lot of various heroes played as different roles. There is also the possibility of dual core lineup.
I remember when I started playing dota, we all wanted to play carries and the general idea was that easy to kill heroes such as CM or leshrac were terrible. It's still the same, everyone wants to be the killer, the one with big ass crits, not the paper CM running at the back, dying every time, spending all of the cash on wards the whole game. On higher ratings it tends to be better though, I rarely see teams like that these days, so just try to endure it or stack up.