I would not mind getting a new hero that can do what current Mercy does as long as they make the kit powerful, I think that this would spice up the support category as well. Also, I would prefer that Mercy regain her original identity with some fixes to her old kit and the removal of invulnerability on her Resurrect.
Now that they nerfed the healing rate maybe they could make the ult charge a bit faster to compensate for this?
Valk is very boring now, I would like to see Valk have 2 rez charges again and only have a 1 sec cast time. (but I know this will never happen)
Valk should feel like the healing version of Super Charger.