the finus factor can't be ignored
HL2RP2 borrows heavily from the formula of the 3 weekish event that ended the helix timeline, which in turn borrowed from ww3rp
the factions are asymmetrical, with greater choice and freedom on the rebels but better structures for roleplay on the union side. i believe that the framework of the union side (copmain kultur of ranks, privileges, rivalries, etc.) gives players an instant sense of progression and satisfaction, this is a side that is also means-tested - you need to be able to pass the application process to play it, there is faction leaders ensuring a level of consistency, guaranteeing that the faction not only has a stable structure to build rp around but it has a consistent tone
compare this to the rebel side: anyone can walk up into your group and talk to you, and that's very egalitarian, but it is hard to create any kind of coherent force to challenge the cmb when you have none of the advantages the cmb structure has (extending to things like supplies, for example - people are driven by self-preservation of their scripts)
the problem as i see it is baked into the formula of the entire server, that we are living a longer version of the final event on helix