In my honest opinion, Mei is too overpowered. This is the case because with the current cooldowns, she is able to use her E ability and effectively become invincible every few seconds. This makes it very difficult to counter her, especially with characters that produce constant damage instead of burst damage, such as Symmetra or Zarya. Also, her wall ability is too strong when paired with her E ability. This is because she can basically block any player from their teammates in almost any spot. This means that her survivability is insanely high and that combined with her low skill floor(because you dont have to aim directly to deal damage on her M1) makes her quite overpowered especially in metal ranks.
Furthermore, Hazard is also a hero who should be nerfed. His block is insanely strong, to the point where he can basically block a Dva self destruct at point blank just by holding block. This means that with one mouse button, he can basically block against any damage in the game. Also, this means that with the addition of a support, he is almost unkillable when he uses his block while getting healed by supports. The mitigation percentage of Hazard should be lowered to about the same amount of Doomfist so it does not feel fatiguing to go against a Hazard player.
In my opinion, the gameplay mechanics of Mei and Hazard should be changed as they are a pain in the butt to play against, not just for new players, but it is also as annoying for competitive players. This has been the consensus from the perspective of several people with thousands of hours in the game. Please fix this, thanks.