Every single 4 or 5-man ult I get off ends up with 2-3 champions literally just walking out of the AoE before the damage hits.
The main issue is that the draw in often doesn't pull champions towards the edge far enough, so it's trivial for them to get out in time. At the same time, any champion with a dash in their kit is virtually impossible to land it on. 1 second is too long.
This feels terrible and unrewarding, especially considering the set up that goes into managing to get that many champions together.