One of the biggest problems with both SD1 and SD2 multiplayer is the lobby UI and design. There are a few problems I see immediately, besides a very small playerbase.
1. The filter system is somewhat clunky as it only brings up the list if you click on the "filters" text but not the checkbox itself.
2. Games with AI should not count as "players" because it is misleading. The server is clogged up with all of these Eugen co-op servers that show 5/10 players (but there are no actual players, just AI). It just leads to extra digging around to find a REAL game. No one plays these anyways, they should just be removed.