The slowdowns should happen after 2450/75, if possible.

IS needs more points to defence, imo.
Joat should either get 25 points or NAS. I always feel it's penalised too hard.

I'm not sure about communications though, as it's tough to limit it to ingame comms.

I would like anonymous races / race names and let the host or a volunteer act as the mail box for players, for say one mail forward each turn at a fixed time?
The host will have to make sure that the players don't use distinctive ship names though (Like I use SeX SFXs and MiL Mine layers).