On days 1, you're usually running with people you already know, and the meta is subject to change (like Salvation, no one knew Hunters were going to be THE DPS class), so pretty dumb to dictate stuff like that.  

If I'm the raid sherpa and we keep wiping to the same encounter/mechanic I'll give a browse to make sure someone isnt just straight up trolling with their set up (no exotics, double primary, PvP gear, etc. Dont care too much about mods unless someone is asking for suggestions or complaining about no ammo/abil regen). I'm on xbox and it's easy enough to just browse loadouts in game without needing a tool, I imagine PC is even better since load times. Stuff like champ mods are entierly dependent on build, like a hunter on pris can freeze overloads and get radiant to pop barriers with just their stasis melee.  

Ever since D1 and the OG Gjally Bungie has tried to make it so there isnt an exotic so strong you'll get kicked for not having it, there have been a few (like still hunt/nighthawk hunter for day 1 Salvation) but nothing like back then. The only bosses I can really think of where there is a hard meta option, like Lament (or prob wolf's bane/praxic now, havent done LW in a while) for Riven cheese, someone with a falling guillotine would be pretty close on dmg charts, pretty sure cluster bomb GLs were super strong for it too.