Yeah, Doomfist would not 1-shot. I was thinking maybe 140 impact damage with a 0.7 second max charge time. Knockback would be 10 meters or so, down from 15 meters.
And Seismic Slam ramping up to 125 damage would stay gone. I think that promoted an unhealthy play-style of dropping off of ledges to 1-shot combo people. So I would make Seismic Slam do a set amount of damage like it does on live servers.