Then I guess Dva’s DM is easier to use 
I’m sorry, but
I have to strongly disagree with you.
I mean, she definitely doesn’t has the lowest skill ceiling, but she most definitely doesn’t has the highest skill ceiling either. To me is she like the Baptiste of the tank class.
DM doesn’t get its max value by simply pressing the button. Because of all it can do, you also have to aim, predict, position well to use it fully.
It takes insane skill to block a Graviton that’s not directly thrown at you.
What tank is harder ?
Not Rein, he’s entry level.
Not Orisa, she’s pretty straightforward.
Not Roadhog, he’s all about landing hooks on whoever is in sight, which isn’t that hard.
Not Sigma, he’s an easy version of old D.Va due to how safe he is.
Not Zarya, she’s almost exclusively mechanical reflexes on her abilities, and her weapon is generous on the aim side.
The only arguable ones are Hammond and Winston, who both definitely have higher skill floors. But they’re not as multi-dimensional as D.Va, which means it’s easier to reach full efficiency.
It’s still a pretty generous ability, even as a 10m range ability.
And even if it’s harder to use than Sigma’s Kinetic Grasp, is it only by a small margin, that’s how ‘skillful’ I consider that ability.
Zarya, Hammond, Winston and Sigma.
The remaining tanks are below Dva in terms of skill ceiling, but is this my own opinion, just like how your opinion is that Dva is the hardest tank to play.
I can tell we both have an opposite opinion about Dva’s kit and the complexity and skill level of it, and I doubt we can agree with each other, so let’s just agree to disagree.
Generous doesn’t mean easier.
Skill ceiling is determined to what you can do with an ability. KG have a very low max efficiency due to its restrictions. Which is fair, in regards to Sigma’s kit.
Zarya’s skill ceiling is lower due to how easy it is to aim and how easy her abilities are to use (it is merely reflexes).
Hammond and Winston are questionable. They don’t have to be aware of things as much as D.Va, and Winston doesn’t even need aim. They are pretty one-dimensional: dive in, mess up the enemy, get out. D.Va also does that, but also has to watch her backline.
Sigma is D.Va without the drawbacks. High damage, but no slow down and more range. Good peeling, but for much longer duration and doesn’t need to move himself. Better survivability. And a stun for good measure.
I disagree.
Being generous means it is easier to use because of the many options it give. It allows the player to have more use for it.
Your challenge was:
Oh it is, there’s no defensive ability that’s harder to use.
I dare you to find one.
Singular.
You asked for 1 ability.
I answered that question by giving a similar ability that has more restrictions than Dva’s DM. You can’t get the same results as Dva’s DM without using more effort. Because of this has it a higher skill ceiling compared with Dva’s DM. Why? Because skill ceiling is the level of skill required to get the maximum results with it, which is in my opinion easier with Dva’s DM thanks to its accessibility and range.
But to be fair, Kinect Grasp may lacks the range and the accessibility, but it does give the player shields, so there’s that I guess.
But if we were to look at their entire kit and role, then yeah, Sigma’s Kinect Grasp may be easier to get value from, albeit not by much imo.
You really seem to think Dva is the tank with the highest skill ceiling, but I strongly disagree with you, no matter how much you try to convince me otherwise.
Dva has a moderately low skill ceiling in my opinion. One that is lower than that of Zarya, Winston, Hammond and even Sigma.
But all this doesn’t matter. It really doesn’t. At the end of the day is it all just our own opinion.
You and I have an opposite opinion about this topic, and neither of them are hard facts.
So again, let’s just agree to disagree.
You (and OP) are comparing the wrong abilities. DM is the analogue to Experimental Barrier, not kinetic grasp. The difference is that in addition to a better ally peel ability in the barrier, sigma has an additional self peel in KG and he doesn’t necessarily have to share them like D.Va always does.
And no, no one can say DM is “easy” since it was put at 2 seconds almost three years ago. Especially after the cooldown and range nerfs. You have to use it correctly and will be punished for daring to eat something useless or not absolutely crucial
I agree with this. I play D’va a lot and got so used to what the range and cooldown used to be that I literally cannot retrain my brain to the changed distance and cooldown. I always use my DM when things a still too far away and then I can’t use it again for a few seconds and never have it when I need it. By the time I finally retrain my reflexes, they will change it again and I will be screwed. 
That… That doesn’t correlate at all! Just because a character is viable doesn’t mean they’re meta. Mercy is viable, but she is sure as sin not meta. People want D.Va viable; it’s not the same as meta.
What you’re describing is skill floor, not skill ceiling.
And you failed it. Kinetic Grasp isn’t harder to use than DM.
You can’t get the same results period.
Kinetic Grasp is much easier to master because there is so little to do with it. You need a lot of practice to master DM.
Yes, skill ceiling is the skill required to use an ability to the max, BUT Kinetic Grasp’s maximum is very easy to reach, because of how it is limited.
So KG’s skill ceiling is very low.
Of all these, only Sigma has the same multi-tasking D.Va has, and he has none of the drawbacks she has.
Zarya, Hammond and Winston also have barely any mechanical requirement.
They all have a higher skill floor, making them harder to instantly pick up, but their skill ceiling is definitely lower.
Actually you’re wrong DM made mccree/76 ults irrelevant. I been said D.va could use some buffs and it wouldn’t bother if she got buffed just not DM that ability is braindead and requires 0 Fukin thought and a crutch for bums with trash fundamentals. The game is healthier without DM, tool is not hard to use 1 bit thx god blizz kept nerfing it.
No it didn’t. Look at them now, they aren’t any more relevant than when D.Va was good.
Hell, Soldier was the best DPS when D.Va was the best tank.
That’s how I know you know nothing of D.Va and how to play her.
History proves you wrong. The game was the most healthy back when D.Va was at the top, before all her nerfs.
https://www.omnicmeta.com/blog/overwatch_hero_meta_report_pc_mar_22_2018.html
If D.Va could DM people and save them it would be better but she can’t with that ridiculously tiny range.
And Sigma has barely anything to do with D.Va, he can’t fill her niche (A highly mobile tank with peel potential), if D.Va was viable she would be played on highground oriented maps.