One thought is whether the Rainham service could instead be diverted to Beckenham Junction or Orpington via Herne Hill to replace the existing SE peak hours only shuttle. Between 2008 and 18 it was a Thameslink route and was far busier then. Would also help with relieving the Sutton trains which are full at Herne Hill by 8am.
This would also have the benefit of 2tph which currently run London Bridge - Peckham Rye - Beckenham (which is bearly used east of Crystal P) to be either used;
to East Croydon giving a consistent 4tph into East Croydon
*OR* continue beyond crystal palace to west croydon via Norwood J
>> this would free up the current Victoria - Streatham Hill - Crystal Palace to continue to London Bridge making a consistant 4tph on that route restoring 4tph into London Bridge. and also to Clapham Junction from stations like Sydenham (making a genuine east west south-london metro service)
Reigate Platform 3 was never funded, nor indeed did the plans ever make it to the point where it was actually considered for funding, as it was effectively wrapped up in the cancelled Croydon project. It seems improbable to ever happen.
What was the proposed changes at Croydon?
The old semi fast CX-Gillingham service should never have been made into a all stations Thameslink service.
I agree given performance and the complications that seem to have been so difficult to resolve to do with sensible gaps at stations like Greenwich.
Reigate seems a non starter for the Luton service given platform length at Reigate.
The original plan was Maidstone - what was the blocker there?
The other plan would be put the Luton services onto the slow lines at New Cross Gate through to East Croydon and terminate them at Caterham, more for platform space than demand on the Caterham Branch.
Could they also take Over Epsom services. Or East Grinstead all day just not in pe@ks?