IMO anything that makes your LLLL.com have a niche of its own makes it better, more rare.
Like the repeating letters, VCVC patterns and other factors such as begining and ending in the same letter. Or something like RTRT.com with duplicate, repeating letters.
Hell, I've even been investing in L--L.coms knowing that there are only 676 of them and almost all are usually taken. Plus I figure if someone really wants a two letter name with my letters they will buy my L--L.coms
I have a few for sale here:
http://forums.digitalpoint.com/showthread.php?t=429335 