Change EK system

We have a balance issue, which could be addressed by discouraging people joining the mass raid party and, instead, encouraging small raid parties.

One way of discouraging people join mass raid party is by giving the EK to a random player in the party in the map.

Why would you make effort running through ML with mass random players for a chance in 1/50 to get an EK?

You better make a small group of 3~5 well coordinated guys to increase your chances.

Plus it would even reward support builds, which barely get EKs.