1) 300 seconds is a huge amount of time to roll on loot. When new content comes out there's always people who want to waste as much time as possible so they can get the new stuff asap by never rolling on loot until there's a few seconds left.

Personally 180 seconds is more than enough

2) When there's a full party of 8, and multiple items that have dropped, it's a pain to go through the chat log to see who rolled on what, and who isn't rolling to try to force people to leave.

I'd like to suggest a special window you can pop open from the rewards window to see who has and hasn't rolled, kind of like the ready check.

3) IF SOMEONE CAN NOT ROLL ON ANY MORE LOOT FOR A WEEKLY LOCK OUT, MAKE THEM AUTO PASS WHAT THEY CAN NOT ROLL ON

Just... please that. It helps every time there's more content added to the game that has lockouts