I would just love two things from the new forge.
1. The ability to control the weather. Imagine a map on the beach with a hurricane approaching from the sea. The hurricane can hit and cause visual changes for Matchmaking and even physical changes in custom games (such as wind speed throwing free floating items like crates and vehicles.)
2. The ability to use your forged maps in firefight. Re-imagine the map explained above, but turned into a survival map with 3 of your friends.
If I had these two things, I highly doubt I would ever have the need to play matchmaking.