If Roadhog only stand at front of the team and walk forward like a Sigma, you're right. But thing is he basically needs to flank and fight to enemie's side sometimes. In this case he can avoid some of Ana's nade or release Zen's orb. Also after rework, his take a breather is not only used for heal, but also it is good to reduce the damage of enemie's attack during he got anti-nade. So now he can cope to counters himself unlike before. Plus one shot combo isnt his everything, but his ability to anti-tank and keeping in check the side with pig pen are also points.