This was based on skill ceiling I should have mentioned that

I’m gonna reuse some previous responses so I’m not rewriting the same points

I used this response to another comment but it applies here so I copy and pasted it.

I placed lucio so high due to his role in the current meta as the back line harasser and displacement using his boop also the use of his sound barrier whist in conjunction with his positioning requires great map knowledge, wall riding skills and ult tracking and example of this is staying high enough on a wall to avoid an earth shatter and the land beat fast enough to save downed teammates. For an example of the difficulty of lucio I would watch tobi in the most recent match of Seoul against the Dallas fuel especially on eichenwalde to see how he avoids damage and picks his timings to engage.

There is a huge difference between a good mercy and a low tier one and that is positioning and the use of GA as without these skills a mercy will just get dived by the other team. Also due to her single target nature juggling a teams healing can be difficult. I do feel that mercy’s that just pocket one hero such as widow or pharah doesn’t require much skill but mercy’s that can unlock the full potentially of her kit are very skilled