Tribes didn't support more players than other games of that time, didn't have a build system beyond placing turrets, had no special world interaction, and maps weren't _huge_ (and for competitive play, mostly short maps were in the rotation)

How about ETQW (2007)? Huge maps, 64 players per match, vehicles, lots of interactivity on the map in general.

https://www.youtube.com/watch?v=e6leg-2Let0

Maybe the modded versions where different?

I remember games with 50-100 players and maps that were multiple square kilometers in size.

Getting a dozen people in and on a dropship in Tribes2 was a highlight of my LAN gaming days. Utter chaos. Superb fun. Too intricate a game for online play but great otherwise. Codename: Eagle hit similar notes.