The Feddies are corrupt and dictatorial, but they're still the lesser of the two evils after the Zeon coup.
It really depends on what organizational facets you are referring to within the early uc. The archduchy was doubtlessly ridiculously corrupt, but for the most part that was the doing of gihren. Had kishiria lived and succeeded with overthrowing her brother at a bao a ku events might have palyed out differently. Likewise, if char had succeeded in a coup. Both of these concepts were covered in the novels, where char joins the white base crew. Amuro dies relatively early ans the plot focuses mostly on char, who was at the time the much more likable protagonist
The later parts of the early uc, such as the events that lead up to the foundation of the TITANS show that the federation wasn't exactly great people. The war was over, zion was. A scattered confederation of space pirates and independanft cells and colonies were choked by the oppressive yoke of federation rule. Despite this, in total violation of treaties signed during the arctic summit, the federation completes development on two superweapons and begins development on two more. Gp01 thru Gp04 would have radically shifted the balance of power towards the federation, and all four weapons, plus the dendrobium mobile weapons platform were in complete defiance of existing treaties. Zions response was hardly measured, but ceretainly not unwarranted, but federation warhawks used the opportunity to create the TITANS, an unaccountable military branch of the main government that would later declare martial law on the colonies and restart newtype experiments that made zion's look humane.
Not to mention that the zion archduchy was only able to seize power because of oppressive taxes and policies that made spacers second class citizens, and the little fact that it was illegal for colonists to come to earth, permanently seperating them from their families...
Sorry for typos, phone keyboard. But my judgement is that the federation is the antagonist faction, even if the original series sugarcoated the fuck out of the conflict.