That completely depends on what kind of content you're targeting.
I am raiding mythic and I full well expect everyone on the team to have boss mod of their choice and WeakAuras the least, because we use custom guild aura packs that often require everyone to run a specific aura depending on encounter.
LFR/Normal? That's like whatever, but HC+ imo it's DBM/BigWigs the least - simply saves you and others frustration of missing obvious stuff.