I'd be surprised of Z had any kind of OD aspect, since Mabel (and probably others) weren't fans of it.
Anyways, Legions ultimately failed after development was halted in 2009 while IA did their whole makeover, and advertising never came back after the launch of Legions: Overdrive since it then became a community project. The fact that the entire IA website was shutdown without even a link to this one didn't help, either. We could've had 20 community maps with the same fun qualities of Frostbyte but they'd be pointless without advertising the game. We've been able to host our own servers and create mods since 2011 and literally NOTHING came of it. No one created a mod worthy of hosting a separate server for like Annihilation, Renegades, LT, etc. Tweaking sever info is child's play, and it's incredibly easy to create something like an Ultra Renegades or LT mod by changing a few weapons variable or bans. But people still played and preferred base Legions, with Team Rabbit getting a brief spike of popularity before dying out.
Part of that was because, again, it was a community project with no real funding for...anything. The other part was due to the licensing issues with IA that prevented the developers from at least spreading out to other websites like Steam, but even something like that would require even more engine work and time. And I'm sure there are a plethora of other things that prevented new players from joining, such as immediately going up against veterans, or the movement system actually taking some time to learn. The game currently consists of the lowest common denominator, if you will. CTF isn't even a thing anymore. People just duel.
It's unfortunate because there are people who still care about the game and want to see it come back, even if it only means a few good games of Legions throughout the week. Poponfu just won't let it go, and is currently reviving Engineer on his own to make it a bit simpler than it was in the past (no leveling, faster deploy times, dumbed-down turrets, etc). I could be partially to blame for that though, since I was really the only one vocal about seeing it return. I remember saying this a while ago, but you'd be better off looking into something Project Z. Legions is somewhat rapidly going the way of Legends, and I'd rather shift my attention elsewhere than watch Legions rot away.