I think literally everyone wants to increase the gcap, and I don't see how this is bad for the server. If the goal is growing the player base then the approach of forcing old returning players to play in a separate guild is going to backfire, I don't see it ever being effective.
The best approach IMO is to slowly increase the gcap to accommodate the rapidly increasing player base. By next week there's probably 3 guilds easily exceeding 20 if they want to. We can increase it one at a time, go from 20 to 25 to 30 and so on. By this point then we can encourage sub-guilds that could help the WoE scene be a bigger deal. Sub-guilds serving a different purpose to facilitate for the main guild is unexplored and it would be interesting to see one day.
I truly hope that you guys, the staff/admins become open-minded for once, and listen to your players. Every stakeholder in every guild wants it, what is stopping us?