It would also make support players all but die out except for the most hardcore supports. Here's why: Pick off the support all the time, and they will never charge their ults to counter DPS ults. In most teamfights, the thing that can turn the tide around the most, is support ults. Either a Mercy rez or Lucio/Zen counteracting an ult stack of Zarya/Reinhardt + DPS.
This will make supports extremely frustrating to play, because except for Zenyatta and to a lesser extent Ana, none can hold their own, and in a 1v1 against a flanker, even they normally won't manage to live.
So in lower levels of play, playing support will be extremely infuriating, because already nobody gives a shit about protecting the support and they often get picked off (while the team spams "I need healing!"). However, with this massive emphasis on taking out ult charge, you will have a dedicated Tracer or Reaper whose sole purpose is basically spawn camping and keeping the support dead at all times. Due to that kind of frustration nobody will ever play healer ever again.
In competent levels of play, you will have to have at least 1-2 people babysitting the support so they don't get picked off by flankers, and if you fuck up, which is easy because of disabling abilities like McCree's stun grenade, the support ult is gone. This will also give a massive comeback to Widowmaker and even more Hanzos, because they can essentially safely pick off the support from a distance by just aiming at them, since it's so easy for them to oneshot a low health target like healers.
Also, Symmetra would become even more useless.
