The Camberley Society are campaing for a link to be built to the SWML:
http://www.bbc.co.uk/news/uk-england-surrey-21988885
They maybe in for a bit of a shock with regards to cost as SCC has the link (so the return from London avoids crossing the SWML on the flat) as £75m rather than £15m! I would have thought that £15m would only allow trains to run into London of a morning, which would be of fairly limited use.
Also, I do not see how (even if there were a spare path into Waterloo) that the TOC would pick to run a service from Camberley (0.5 million passengers, even adding Frimley and Bagshot doesn't even make it to over 1 million passsengers) over most other places which would desire more trains (even Hook has about 0.65 million passengers! Let alone Woking, Farnborough, Basingstoke, Southmapton, Portsmouth, Sailsbury or Guildford).
That then also leads to the point that even if a path existed and was allocated to Camberley I very much doubt that it would run fast once it joined the SWML.
Overall the best solution that they could hope for is an extension of the Woking stopping service, which wouldn't be that much slower than the existing route at about 65 to 70 minutes compared with 75 minutes. Although that would then allow people to change trains at Woking for a faster service, however allowing for a 5 minute change time (which is required in the morning peak as the bridge at woking can get very busy) that would be (just) about 50 minutes, however in reality it's more likely not to save that much time.
It then leads to the question, is it better to spend £75m on a east bound link which will require a change to get to London within a reasonable time and a change to head west or to spend the same money on a link west which requires a change to head to London but allows a direct link to Farnborough, Fleet and Basingstoke?
My vote would be for a west bound link, as the trains to London tend to be quiter at Farnborough then they would be at Woking (i.e. more likely to get a seat). With the extra passengers at Farnborough it could then see extra services calling there benefiting more people. It provides a direct rail link between Camberley and places like Farnborough, Fleet and Basingstoke which would likely generate more rail passengers than a direct link with Brookwood and Woking as there are many people who would want to travel between the two lines and can't so drive. It would also enable a new service to be run (possibly Basingstoke to Ascot) which would be self contianed and could be useful at time of delays east of Farnborough.
I can understand the case for the east bound link; less time standing on a peak hour train from Woking than from Farnborough. Why make the journey longer than needed by going the wrong way? Better connections with other stations heading towards London.