The higher number ranks are supposed to show how good you are. If you can't solo a legend lost sector, guess what that means.

I soloed one five times…I wish I could remember which one as it was super easy. All you have to do is get into a little tunnel and stay there killing everything. Nothing can touch you. Takes about 30-35 minutes each but there were soloed and flawless.

'Chamber of Starlight' in The Dreaming City can be cleared flawlessly in 7-10 minutes on master.