Unifying the Unvanquished, Tremulous 1.1, and Tremulous gpp communities should be a top priority for Unvanquished. Remaining separate is futile for all three games. But we need to take a practical approach to achieve this. We've seen how the remainder player bases (particularly 1.1 and gpp) have been extremely reluctant even after so many years to try out the other two games regularly. Each game has its own unique game style (and in the case of gpp & 1.1, their own unique mods) that the respective communities enjoy, and each game has their own unique community of friends. I have determined that the source of reluctance to try the other games regularly is that they get the sensation that if they try out one of the other games, they would be forever giving up the game styles, mods, and friends they know and love.
What is needed is a solution that allows each community to seamlessly play game styles & mods from any of the three games and be able to play with members of any of the three communities without leaving their own community, i.e. merge the communities. After discussing this with theinvisiblman, the most practical solution I see so far is a launcher that shows the server information of all 1.1/gpp/Unvanquished servers, switches seamlessly between all three clients, and comes with an installer that easily installs all three games on windows, mac, and linux. Right away you would see players trying out new games without the fear of losing what they know and love, All three games would have a much larger community since they would have one merged community, and developers from all three games would be inclined to work together to achieve things that separately they could not achieve apart, and some server hosts would be open to hosting servers for more than one of the three games. You can call it something like The Unified Unvanquished Game Launcher to take advantage of branding.
Eventually when Unvanquished is ready to support mods, mod developers from 1.1 and gpp could then port their mods to Unvanquished taking advantage of the superior game engine, and the communities would shift 100% to Unvanquished since they would not be forever leaving behind their friends and favourite game styles.
If the Unvanquished team wants to take action to increase their playerbase, they should make this unified launcher their highest priority and get it released as soon as possible.
Edit:
By the way, some trem 1.1 & gpp players are trying to work together to reunite the communities. Here is the link: http://forum.acidtu.be/viewtopic.php?id=529.