No - nothing. I do get lag in fleet - at least I did before I stopped going there.
Try Imp side - less of a problem
Seriously - although I don't have a higher level character on rep side, so I'm not sure about the upper levels - no matter when I play there's at least 100 people on, up to close to 200 (not on fleet, on planet). Imp side - the lowest I've seen was 15-20'ish and the highest 60 or so.
Come to the Dark Side ... we have cookies and shock collars