AEM is a pretty good addon
I like it because it keeps it simple
Unless they are a large scale deal (like thrawn's revenge), i dont like mods that have dozens of ships per faction, may of which do the exact same thing but just are there because they LOOK cool or different.
It does add some ships to factions: MC90, Imp2, acclamtor2, MC104 (supercapital, comes with escort fleet) MC40, Victory2, strike cruiser, carrack, lancer, k-wing, e-wing, Assault frigate MK1, ACC, t3b, and many other land and space units, but not too exessive. Also re sizes units to a larger, but not complete, degree of accuracy.
It increases plant count to 72, and adds some only trainable on units to increase specific planet's role in strategy
For instance,:
Correlian battleship, destroyer, frigate only on corellia
Sheilded t3b and t4b only on some planets
Droid units only on some planets (aat, munificent, commerce guild destroyer)
Gorund x-wings
All this makes you plan strategy in a more complex way, because you must go for what you need
Its fun to play, but one GC took me over 72 hours on hard
I dont have any proof, but i think it decreases field of fire slightly, increasing the need for tactical maneuvering in space. this gives a frigate attack group a chance against larger vessels.
NOTE: THIS IS A EAW MOD< NOT FOC