Confed makes up of about 500 star systems and during the it's height in the Kilrathi War had 15 carriers or so, probably a few thousand destroyers, cruisers and the such. At its hieght the empire composed itself at 1 million star systems with thousands of star destroyers, and hundreds of other ships per each one. Every planet worth anything was protected by sheild generators that made it nearly impossible to attack from orbit.
Coruscant has more people on it, than the entire confederation, and it's shields have been said to be able to repel the superlaser, and you won't find a fault line on the entire planet. The only part of the world that you can still see are the tips of the Manarai Mountains, the highest chain on the planet, everything else is covered by Kilometers of city. My information says Corascant could house anywhere from 60 to 600 billion people. That is just one world from a thousand thousand. There is a Star System in Star Wars that is defended by two sector fleets like 4,000 ships, which of those 50 are star destroyers.
Vader's "Death" fleet was 40 star destroyers in size centered around the Exetor a 16.4 kilometer star destroyer with over 500 cannons, each star destroyer is nearly 2k long and has a crew of 50,000 men.
Even at it's weakest, 20 years after return of the Jedi, the empire still had some 300 systems and 250 star destroyers, not counting other vessels, such as dreadnaughs, Nebulon-B Frigates, Carrack Light Cruisers, Lancer Frigates, and Strike Cruisers.
There was a reason why the Rebellion only fought one major fleet battle in the war,they would have never won.
It would be pure attrition, the Empire would steamroll over Confed like we did Iraq in desert storm.