They are probably the least impactful in the game right now. They can get easily countered or ran away from. Require either good aim or luck. They’ve become somewhat zoning ults.
A DPS ult doesn’t guarantee a win fight, meanwhile you are almost certain to win a fight with Tank or Support ults. 
I could write a whole list of counters for each Tank and Support ult.
They really shouldnt, that would not be fun.
Shatter didn’t have any followup. D.Va bomb failed to kill targets. People ran from Ram so his ult was just random glowing. Doom’s target moved out of the easiest ult to avoid. People walked way from hampter mines. Winston jumps around angry not killing anything. Zarya, like Rein, got a grav with no followup. Same with Sigma. Hog got focused and died during ult. JQ missed her charge in getting zero elims. Orisa let go of ult too soon and didn’t kill anyone.
Vs
Soldier/Reaper pressed Q and got ez kills.
It’s easy to pick and choose with exaggerated claims. All roles can whiff their ults just as much as they could get POTG with them.
It’s not about support/tank ults vs dps ults. It’s good ults and bad ults. Is deadeye garbage? Yes. Is Blade, Copy, Pulse Bomb, Tire garbage? No.
Hence why widowmaker should be a tank
Illari has a better DPS ult than Reaper and Cass LOL
She also has to actually aim her ult and then continue to aim and follow up on it, it’s not as easy as their ults but it can also be avoided/blocked/eaten/deflected/cleansed/survived.
If a DPS hero has a good and consistent damage and good kit/abilities it’s actually fine and normal for that hero to not have crazy Ult. Not every Ult in the game should be about winning the team fights and deleting the enemy team. Wtf??
It’s all on how the Ultimate is used
How are we defining aim, again? I am pretty sure Cassidy has the same aim requirement that she does. Looking in their general direction is not aiming, cuh.
Albeit, after playing her quite a bit, I have to admit that her Hog sized hitbox is a complete and utter detriment. You do need to make sure you are not accidentally firing it into walls or succ abilities. And it used to be bigger, freaking size queen. 
Are you a fool? Or just purposely being dense? Illari’s ult is a projectile, Cass ult is literally just a lock on…
youre the dense one here. hes saying illaris ult is not as hard to aim as Cassidy’s primary
Please do would love to see the list
Okay thats on rein he should have fire strike and charge if hes shattered
And this is why people don’t take legitimate support complaints seriously, because some of you say stuff like this or worse, genuinely believe it.
You really just said Illari’s ult has the same aim requirements as Cass’ and expect me to believe you’re not just blindly hating the character and downplaying her kit just because she’s a support?
If the enemy team is scattered and all hopping around in different directions, Cass can stand in one place and hit/kill every character on his screen, Illari literally cannot. Her ult is OBJECTIVELY more aim-intensive than Cass’ and Reaper’s and there’s no argument against that fact.
Yes.
Yes naked blade is bad is it the worst absolutely not i owuld put 5 ults below it like pulse, dead eye, dragon strike, barrage, and artillery (not on a specific order). Theirs a reason its always called nano blade when talking about it doing anything naked blade just sucks at killing do to how much healing and immortality their is.
Insanly inconsistent and sometimes just worps out of existence doing no damage.
Super relient on the enemy teams comp.
Tire is the only solid ult here.
Yet people fear illairs ult far far more then cassadys
These takes get better and better.
Ya a lock on that doesnt work right and you have to understand weird overwatch geometry to even get kills with it because its so badly coded its just the worst ult in the game