i always stay away not that far la... normally within reaper ultimate radius behind...i always kena reaper death blossom from top one. you played dota you know the common thing la, group together is good thing yes that is true but sometimes people with AOE ultimate is killing us even faster
sometimes finding spot like higher ground to see clearly or at least spam fire / diverse attack force on front line (i just need stay behind and harder to get hit, that's all)
just yesterday is not that fortunate when i move away and want to go 2nd floor on volskaya map, thing is that moment also enemy don't have any movement at all... a scout is needed for reporting where they are going to... because that time as mentioned, they are literally stand on point facing at main gate and do nothing.
normally we play sure got 1-2 DEF/ DPS hero move front few inches to shu shu away enemy or just engage and jsut make enemy busy ...
for the yesterday my solo case..no... they are litereally sitting duck unless they got hit by something. at that time 1 zarya ultimate can just wipe 6 man team if i stay on point B.

if i play mercy, ya stick.
zen, stay away but keep line of sight unless enemy reaper chase my ass off

Agree, regardless whether you are on atk or def, I always prefer 5 stick - 1 flank or 4 stick - 2 flank formation.