some maps have literally 1 choke point.
genji CAN counter, genji is not a reliable counter thought. because its a skill match up, a smart bastion can just wait for genji to parry then shoot him in the face afterwards.
We've hit pretty high skillcap in our group now and were fighting an equal team for like 10 maps+, and barely ever was bastion used, and when he was he just didnt perform enough. His ult is good, but such a stationary target is easy to take out, either through flanking or simply Hanzo ult. Its a good pick in lower tiers i guess because he literally takes no skill to play, the only thing is deployment and even then he's reliant on having a shield up. Good players deal with it relatively easily. Holding one chokepoint is best done with a wall of really tanky heroes, a couple of dps's or a mass turret spam with some tanky heroes. We had no chance whatsoever against Symmetra + 2 Torbjörns, we would take down the turrets and builders but at that point we'd be dead to the remaining players. Crossfiring turrets too good.
The strongest thing we've fought so far that absolutely demolished us was Mercy + Pharah, the Pharah was a really good player, and with a constant healer following at heights were we could do jack shit, it was just unstoppable. But im not sure if we pulled out a sniper for that, so we may have been at fault.