Sort out Customer Service
I think it's good that DSG are trying to keep at least some high-street (/retail park) presence and revamping their stores accordingly, but the main reason I don't shop in any of their outlets is the appalling customer service. If something goes wrong with anything you buy from Currys/Dixons/PC World, then you are in for a world of pain trying to get it repaired/replaced/refunded.
Whereas, if I buy from (e.g.) Debenhams, or Comet, I know that my problem will be dealt with sympathetically and efficiently. I'll happily pay a 5% mark-up for that!