Res wasn’t broken to begin with, it was only perceived to be by the community. So, I have no problem with making it an ult again, but maybe others do. Again, I believe the change was made to appease the community. From a design point of view, the mass res ult was fine.
Where a player dies is very random, and encouraging the team to get into a death ball for res isn’t something I’m a fan of. Lucio, Brig, Moira and Ana all have elements to them that require the team to gather into a small, tightly compact “death ball”. I always liked how Mercy was different in that she synergises very well with a more spread out, co-ordinated assault from multiple angles. I prefer that sort of gameplay rather than the “Everyone get into a ball” gameplay.
This is a pretty decent thing to do, as it allows Mercy to regulate healing output when it is required.
In summary, your changes aren’t too bad in that they patch up a few issues with Mercy, but I’m not a fan of the short range on the res and this rework doesn’t necessarily add much skill expression into the kit.
Here’s me mighty Mercy rework, if you care to view it: