I don't know if this is feasible/possible, but it would be great if there was a way to see a list of all the players in your world in a single list in the menu and each avatar's impact on rendering time (how many draw calls maybe?) with an avatar on/off beside each person in the list.

Often times I am in a room and everything is smooth and fine and at some point someone with an awful unoptimized avatar will join and then I have to play detective to figure out who it is by disabling people one by one until I find them, then going back and re-enabling people. I have quite good hardware but I find that playing in VR I have to do this quite often.

I also think that giving people visible metrics (draw calls? material count?) about their models might help the push the community toward more optimized models in general. If you join rooms and in every one your avatar is towards the top of the list for performance impact it may encourage you to pick a less impactful avatar.