The gameplay is MUCH more shallow.
No seeking weapons of any kind, and the 'customizable'-ness of ships really makes all the battles bland. Each and every mission becomes an exercise in 'close and hose' and that's really all there is to it.
Worse, because of the weird 60 degree weapon arcs, all the ships just end up closing and spinning like tops to bring weapons to bear.
I think Taldren recognized the blandness of this tactic, and so tried to make close battles undesirable by having the 'angular velocity' (IE, how quickly the ships are moving across each others bow, basically) be a HORRIBLE penalty to hit. Of course, the easy solution to this is to just tractor the enemy ship.
Yeah, only 4 races makes it even more bland, but, honestly, given how little difference there is between any of them now, I don't see how adding any more would have made any difference.