As far as I can think of for some of these questions. Popular KZ servers are based on smooth and ironed out consistent servers with no lag issues etc. which I'm sure SG can take care of. As far as player count, this can be established for more popular well-known communities (like ours) Late night servers that contain high pop that I noticed are KZ/Surf/Bhop (our bhop server included)
Gameplan, hard for me to answer because I'm not sure what SG's limitations are and what are requirements for server launches are.
Any gaps or anything, nothing I can think of off the top of my head,
This is definitely a step in the right direction.