I've always been slightly surprised that the CLPG appear to favour extra stops at Shipton over Ascott. That's where the lobbying appears to have been focused in the past, leading to the extra Saturday calls at Shipton.
Yet, Ascott station is right in the village, while Shipton is not. Neither station has a proper car park really, so if we're just talking local pedestrian/cycle users, surely Ascott has better chances of growth if an improved service was offered?
It's not a question of favouring one over the other, it's about getting a decent spread of services at both places. Yes, Ascott station is in the village, but it's a small village, 560 people at the time of the 2011 census. Shipton-under-Wychwood and Milton-under-Wychwood are effectively one large village and have a combined population of just shy of 2,900, far more than, to take an example up the line, Honeybourne, which has a population of just over 1,600, but far more trains, thanks in no small part to having a platform able to accommodate a three-car Turbo set which made it easier to add stops post-1993, whereas Shipton, as Buttsy notes, has the problem of the two-car platform for Oxford-bound services.
The better Saturday service at Shipton is nothing to do with lobbying, it is as a result of the 2006 franchise agreement, which left the Saturday service at Shipton largely intact - presumably on the basis that the station serves more people - while withdrawing all the Saturday stops at Ascott, Combe and Finstock - which until then had a better Saturday service, albeit as request stops, than on weekdays.
