Reason to wait for 20+ people is simple....because most players can't dps their way out a wet paper bag.
Notice in that vid that all the players in that instance did min 2 mill each.
On on PC in NA prime time...people are struggling to do 200k! Like seriously, I participated in one fail last night and did more DPS than 7 other dudes COMBINED...lol?
Here's what I think, people are just there for weapon exp. Also, many are using BMGs b/c I do believe that the WM fight is one of the best places to level them.

