Without descending into the gratitous orgy of Yzak-loving...

Suits were outdated, but I do think hving more coordination in the ZAFT forces, with creating special units for closer range (Duels) and backed up by long range ones (Busters) would be strategically genius for ZAFT up in space with all that room to employ formations and specialized squadrons. Like knights in front, archers in back. This type of specialization would benefit suiting the skills of the soldiers, rather than putting a guy who sucks with a sword into a position where he may get entangled in melee, OR putting a good scrapper in a position where he needs to hit a target from far away when he has terrible aim. AND most imporantly, eliminate alot of the confusion that always seems to be going on in these battles. Granted it wouldn't look as cool, but the military thrives on organization and specialization, and just purely developing and issuing suits that arent geared towards pilots and unacceptably throwing them out there into a chaotic battlefield...

Wait, wait I'm getting off topic here. But you see what I'm saying? You could even have a specialized covert ops squadrons of Blitz units too! And put DRAGOON units to the command ships and defend against huge missile strikes. Plus, how about some formations so you dont have all your battle ships and cruisers going willy-nill all over the place?