Well, I guess there are really two different definitions of "crowding".
One is related to having so much people on the server we fear the hardware can not cope well with it, causing lag and such. According to what has been said by Vyvyanne, this will not be the case once the hardware migration is done. So forget about it, hopefully.
The other is probably just a lot of people on the same server, competing for quests and resources and what not. Crowded in the sense of many people on the same place all the time. That is different from the one above and we will of course see a lot more people running around on the remaining servers, so yes, for some that may be a concern. In my opinion this will have to be dealt with somehow, since you can't very well have a queue of 15 Toons on each Ore resource, as a exaggerated example. Even if they experience no lag.