The service has obviously been quite badly degraded. If you assumed a train leaves Victoria at 12:00, and calls all stations to Maidstone including St Mary Cray and Kemsing (also Barming etc) then you get to Maidstone East at about 13:04.
If a 12:30 leaves and then calls at Bromley, St Mary Cray [don’t much like the current bad spread of departures on fast Victorias, so make sure that extra stop is in there], Swanley, West Malling and Maidstone then you’ve potentially got an arrival at Maidstone of no later than 13:26, and then all stations down to Ashford.
All you have to do then is to gently tuck a Charing Cross to Ashford in behind, which stops at Swanley, Otford (new connections), Borough Green, West Malling, Maidstone, Bearsted and then Ashford and all the people at local stations east of Maidstone are then catered for with a change at Ashford, and you can allow passengers on a fast Victoria to jump ship at Swanley onto the Charing Cross for Otford and Borough Green.
That then allows that Charing Cross to be extended to be the “fast” one, so Ramsgate via Canterbury or whatever. One assumes the journey time would be relatively competitive as well, compared to the current slow service via Tonbridge.