Yes. Nomadic tribes have maintained their culture as nomadic tribes for centuries. Not settled cultures that suddenly become scattered wandering nomads for generations. Totally different
You're attacking a concept that's near universal in strategy game design. Calling them factions instead of races doesn't make it any different than gaining new units in C&C. A preset tree is a preset tree.
That said, I would prefer a more interesting tech tree implementation, but the faction and start out system is hardly cause to require it.
I'm not attacking it. It's a great system that's worked fine for many games. What I'm saying is the traditional faction system doesn't make alot of sense given the game's premise so why not try something more unique and interesting? A dynamic faction system is something I've never seen before but could be really really cool if implemented well especially in a game centered around customization.