Honestly, it’s easier to block a Rein Ult with Mei than with Orisa.
And I play plenty of both.
You got pretty much the whole time Rein is saying the word “hammer” to react.
And since the wall starts at ground level, it’s mostly impervious to getting fouled up by lag.
Alternatively you can Iceblock the Ult, cancel, then Wall. And harass people with freeze who try to get past the wall.
I’d say Roadhog is a “heavy” DPS with some tanking abilities, and Mei is a Tank with some DPS abilities.
If anything, given the way they are played Roadhog is more of a DPS than Mei is.
I figure votes would just be something that shows up in the chat, but something that obscures vision during combat.
We need a better role system before role queue becomes remotely viable.
So I hear UnitLost is gonna publish a RoleQ interview today with Jeff… 
inb4 Jeff says “I have faith in our matchmaking system”