Not a chance for CDG, the 5x daily service was dropped in 2004 because it is as simple as this:
BA from Gatwick
(eg.) Tunbridge Wells - Gatwick: 30 mins approx by car
Airport check in: 1 hour 30mins
Flight time: 1 hour 10mins direct
CDG to central Paris: 40 mins approx
Total: 3 hours 45mins
Eurostar from Ashford
(eg.) Tunbridge Wells - Ashford: 30 mins approx by car
Check-in: 30 mins
Ashford - Paris: 2 hours
Total : 3 hours
Spanish routes have easyJet on them fairly conclusively, as well as Ryanair picking up any of the rest of the slack. I don't think there's any room for BA because the average reason for going to Spain (by some distance) is the beach holiday. The same is the case with the Canaries. A once daily Iberia/BA service from/to Madrid would be welcome, however.
Malta has already got easyJet and Air Malta as well as Thomson/Thomas Cook so I think BA could only make so much headway here. You've also got to bear in mind that the 737s are getting rather old and will need replacing soon, so until that process is underway it is unlikely that BA would want to expand short-haul at LGW without facilities to do so.