In an unfamiliar raid, with 11 identical blue dots moving around the map, it can be very difficult to figure out who is where.
Here are some suggestions for making this process easier:
1) Give each player in a 6 person party a distinct color (i.e. blue, red, yellow, purple, orange, green) instead of just blue for all. Use that on the minimap and put it next to their name in the party list as a key. For 12 person raids, the second 6 characters could reuse the same colors as the corresponding from the first 6, but add a black dot or something to the center for differentiation.
2) Highlight the dot of currently selected player on the minimap and map so it is highly visible and noticeably contrasts with the others.
3) Positional voice chat. Please create an option where we can get positional audio queues (delay left/right channel appropriately - simulate pinna occlusion for voices behind you etc.) to apply for incoming voice chat to better figure out the direction of talking teammates relative to my camera. I don't think you'd need to scale volume down for distance since you'd want to hear all incoming chat equally well but maybe add an acoustic quality like subtly increasing reverberation the farther they are away. You could couple this with showing a "talking" symbol or animation around the character's head.
4) Rotatable 3D map. A simple 3D wireframe automap (like Descent's from 15 years ago) would help to determine elevation of teammates as well as the lateral position we get from the current overhead view.