There's no way there's 28000 real forum members. These days everyone's got at least 3 alts ( and make that 30 for folks like Lemon )
Based on another community of a game released at about the same time I'd say the true number is about 12000-15000 at most. Probably over half of them are ancient accounts of people who would not even be interested anymore, a couple hundred are banned accounts, few thousands are people who tried it once and then concluded it's not for them ...
Realistically, without new blood it's unlikely the mod can get a much more active playerbase again.
Let's face it, it's an old game / mod, the numbers are right where you would expect them.