Noticed the real problem isn't the HP (doesn't help) but the cooldowns. When we took point A on attack (got to 3/4 to the end) the first point was almost held solo by a Mei who just iceblocked every 3 secs and managed to stay alive far longer then she would normally, long enough till reinforcement or two arrived who almost died instantly.
Or the constant shield from Winston doesn't help either.
It's hard tbh to win on attack but it doesn't help if you're team is full of people with players like Hanzo because it is possible to push if people pick the right chars.