I think the faction imbalance is going to hurt both factions. With so many sith waiting for a republic player to show up and gank him, the republic players with not have enough numbers to even score a kill, much less feel that its not real pvp but a gank fest for the sith player benefit.
In turn republic players will probably just not show up on ilum and the sith players will lose out on their dailies and weeklies, course you will have the occasional new person who shows up to see what ilum is about.
If they are going to do something like this, maybe they should open it up and make it a FFA pvp. Just a suggestion.