They need to fix his tempo.
The difference with Doom compared to other dive tanks is the lack of constant aggression or pressure.
Winston can get a burst of damage off his jump and melee combo then cleave into enemies.
WBall can do constant fireballs or swinfgs every few seconds across an entire team then commit with a multi hit slam. He can still even unball and start firing his guns.
Dva can boop targets, launch an array of DM, micro missles, and has infinite ammo on her shotguns.
For Doom…his tempo drops hard when blocking or trying to self heal during meteor strike.
When you look at the ultimates too its very much different in their effects. Dva’s bomb makes everyone run away and find cover. Winston can knockback entire teams and becomes a giant bullet sponge. Wball’s minefield can deny an entire area for 15 seconds and becomes such a huge distraction.
For Doom’s Ultimate. He leaves the fight for 3 to 6 seconds…which then all enemies can scatter and fight freely without Doomfist being there for his team.
The issue with Doom’s kit is that he has high burst moments but his low moments during the tempo in his fighting rhythm fall off significantly to where he actually just stops fighting entirely in these huge passive moments that add nothing to the current fight and are easily countered.