I would propose instead to increase the frequency of calls to those stations. They have comparable usage to the Dorking-Horsham stations which benefit from a 1tph (albeit 5.5 days per week) electrostar service to/from London Victoria.
I'm not sure why those stations are 1tp2h, but there usually seem to be people getting on/off at the small stations between Dorking Deepdene and Shalford. I can't speak for Betchworth because I rarely get the train in that direction. Dorking West is an interesting one because it is the accessible alternative to Deepdene, although the pedestrian journey between the two is not the shortest or flattest. Additionally, tickets are often sold to 'Dorking Stations' so actual usage figures are hard to decipher.
I guess that when new trains with better acceleration come in every station will get at least 1tph, but I'm not sure if signalling changes would also be needed to achieve that and the coveted third train per hour. Gomshall should be the focus of any increase in service frequency in my view, as it is the busiest of the shacks and has lots of nature/walking appeal like Boxhill and Westhumble.