Devil Dino is not as OP as everyone thinks, He's just an actually strong tank.
Flex player here, but mostly tank. (I main Peni, Groot, Strange. Occasionally Mag, Thor, Rogue, and Angela.)
Dino is not as OP as people usually think. Most people see top competitive players complaining and hop on the bandwagon pretty quick in my opinion. I've also seen high ranks complain a bit too, though not as much.
Dino is a very strong tank, no doubt about that.
I believe that alone is the reason why so many are complaining, including other tank mains.
For a long time, DPS and Supports have run rampant with OP characters, and have only gotten a slap on the wrist with a few exceptions, and are clearly the most popular roles compared to tanks.
The one time a tank was strong was prime Emma; she was actually op, but got nerfed to the ground, and with this shiny brand new tank actually feeling strong for once, even with obvious counters, it makes it difficult for people to adapt to it, thus leading to the complaints of dino being overtuned.
Now, there are some very small changes I think would help him not feel so oppressive to other tanks, but still feel very strong and force players to work as a team: compared to picking the counter character with a free win button.
Dino's Lazer gives bleed, slow, and knocks down fliers. Getting rid of the knockdown or the slow allows characters like Angela to not be completely dismantled by him. (Dino can still use his leap to grab fliers, but poke meta does more than enough to stop most fliers.)
Slightly Increasing the cool down on his leap/grab, will make it less annoying for tanks since Dino will be forced to save the grab for characters like DareD and Venom.
These changes will stop him from going down the path of Emma and now Tankpool, where they get nerfed into the floor and lose a lot of their identity as tanks.
TL;DR: Dino is not OP, a tank that actually feels like a tank, which people aren't used to.
Remove Knockdown or slow from lazers, increase grab cool down a bit so he doesn't bully tanks as much, and increase the cool down on his grab/leap so he has to use it more sparingly.