Personally I think that the major question will be if the moderation team will be ready for more people to ban since people will automatically assume that since Classic is in the name that they can conduct themselves the same way when they were teenagers in 2009 when community guidelines have massively changed since then considerably.
The good news about having more players is that you open the potential for more people to host too, so it's hard to say whether or not actual playercounts/servers being filled will be more of a problem than it already is. Let's be real, as of right now on a weekend night you may have multiple server status windows up anyways set to "Join now" to actually join a VF4 server. Might end up being better because more people that have consistently played on those servers may support them to get reserved slots; I know that I have been considering it since I play almost exclusively on these servers when playing TF2C and since I play pretty much for a month or so out of the year at a time, it works out nicely.