I don't think this has anything to do with the way nexuiz hs different mechanics at all. I think it's what makes Nexuiz unique even, the thing that keeps you coming back.
And yes, considering the graphics limitations of nexuiz, I wouldn't play it if it played exactly like every other FPS games out there. I myself am in a team developing another game which is very much a traditional FPS. Yet I still play nexuiz, simply because it's different.
The issues are simple:
1) The current weapon balance favors the 'noob weapons' horribly. As has been said in countless arguments in IRC. The Machine Gun and Shotgun are currently probably the most powerful easy-to-use weapons in default nexuiz. Which basically means, players will prefer them over the harder-to-use 'higher weapons' - e.g. rockets/nexuiz/grenade launcher. Damage-per-second-wise, they simply are no match for the spammy death of MG and the easy availability of shotguns.
As such the results are predictable - they will never take the effort to learn higher weapons. The weapon 'heirarchy' is upside down.
2) The current crop of 'elite' players do little to help newbies. Once upon a time, experienced players would go out of their way to teach a noob how to bunnyjump, how to laserjump, etc. Now they just waltz into a server, kill all the noobs, and leave. Usually without a SINGLE word spoken. Or worse, brag about it.
How many people actually say 'hi' anymore when a noob says 'hello'? How many people take time to stop and type a longwinded explanation of how something works when a noob asks them, even when they know it would mean their death? You don't. You'd sooner have someone tell you to 'press f10' than actually tell you. How many people play the game for the fun, not for the scores? You don't either. You'd have elite players quitting as soon as they start losing, players typefragging simply because someone did that to them once, skilled players joining stacked winning teams when they should've known better, players ignoring chat or worse, actually telling people that 'this game is for fragging, not chatting".
They learn soon enough that arrogance is the way in nexuiz. So they stop asking. They become silent players too, no matter how bad they are.
When I first started to play nexuiz. I was like them. I didn't have any idea how to laserjump. I played like that for a week or so, then asked someone. I still remember his username, though he does not play anymore - Bender. We were the only people in the server, and he gladly taught me everything from laserjumping to wallclimbing.
I don't see that anymore. We don't have communities anymore. Even the clans are dying. Everything is exclusive. From the hidden servers to the 1on1 events that noobs have no idea about. Where before we had 'teaching' servers. There was a clan/community which focused exclusively on teaching new players I think. And there were clans which took in less skilled players and taught them, instead of headhunting for the most skilled players around regardless if they were actually assholes ingame.
P.S. The reason why I like wide open maps is not for camping. It's because closed maps restrict speed. If you have a ping higher than 100 you'll have great difficulty executing the 'wall-bouncing' elite players take for granted. Much less at my normal 300-400.
P.P.S. I haven't played nexuiz for a while now. It just gets too frustrating. The team stacking, the unfriendly skilled players, etc. etc. Might not for a while still.