I agree. Historically, of course nations built/trained units and ships in the same region. But for game play i think the current system is the way to go. As it is the AI have difficulties keeping up with you in production of ships most of the time.

We all have those couple of teritories that just chuck out ships the whole time and don't produce any troops anyway so there are ways to counteract this.

Think this one would be difficult to implement too if CA decided too.