so the riders who might benefit from LA's loss are themselves proven or suspected drug cheats
(Assuming USADA can force UCI's hand) - yes
Though LA probably falls into the "suspected" category; Ullrich too (AFAIK) never failed a test ...
Rhetorical question: how low down the results list do you go (in the post-Festina, Armstrong era) in order to be confident of finding a clean rider?
On that basis, there's little point in "stripping" LA of his wins; even if that were to happen, in the eyes of many he'd still have "won".
Better (maybe) as others have suggested, just to draw a line through the entire period, with a footnote saying "Some results may have been performance-enhanced, but the effect of this on standings cannot be quantified; but hey - wasn't it all exciting?"