You need to think of doomfists ult like an archery target
It has multiple rings which do varying amounts of damage.
The bullseye is the true inner ring and did 300 dmg
The next ring also did 300 dmg but was actually the outer ring due tot the fact the outer ring scales from 300-0 depending on how far away from the centre you are.
The next ring 250dmg
The next 200dmg
The next 150dmg
… all the way to the outside of the ults radius where it does 0 when outside
Now what you have to realise is to simplify the visual for the player they combined the inner ring and the part of the outer ring that did 300 damage into one visual. Basically they combined the bullseye and the closest ring from the centre into one ring. Otherwise if they made it accurately only represent the inner ring it would be confusing as a player could be outside the inner ring and still take the max 300 dmg. So they simplified it by making it so if you are in the inner ring it does 300 damage and everywhere else it does less.
Now with the recent DF changes. The outer ring no longer scales from 300-0 but 200-0 and as such the closest ring to the centre no longer is needed to be combined with the bullseye as it no longer shares the same damage value. Thats why it looks smaller. The original inner ring wasnt just the inner ring but also part of the outer ring combined. When they nerfed the damage of the outer ring they removed the visual to show that.
Doomfist’s ult was bad in the first place but they decided to nerf it so immobile heroes can escape it which is actually a bad reason it wasn’t that hard to avoid but they still did it
I absolutely hated doomfist but the nerfs he got were just bad the only nerf that was good from all of them was the uppercut one where they reduced the loss of air control
The others were just there for no reason I haven’t seen a doomfist since these nerfs
Oh boy, prepare to be shot down by salty support mains for saying DF’s ult is bad.
From them it used to be a cheap unavoidable, uncounterable, ignore LoS regardless of distances from center instakill.
Now it can’t even kill a low HP baby D.va. And still there are people call it a good ult.