Well it doesn’t have to be a long one. Could be short like Lucio’s. Enough for counterplay but not too much.
And again the idea is to remove Hide and Rez. So sure it would hurt 5 Man Rezzes a lot, but you can still Tempo rez.
Ideally you’d want to Tempo Rez a lot with a cast time, so your team that is still alive can protect you.