There is a possibility that Stalybridge could be gated as well, sometime in 2018. It would by far be the easiest station on the TPE network to install barriers at.
Regular user of Stalybridge here - do not agree. I have fairly serious doubts gates would work. The gates probably have to be on the flat, so they'd have to be just behind the ticket office windows. To do this you'd have to relocate the TVM (and there isn't really anywhere else to put it), and permanently lock the manual side door, forcing everyone through the gates. Realistically I think you'd have to remodel the ticket office to an extent to fit them in. The ticket office is also pretty crowded at busy times so the barriers would probably be obstructed fairly often, on both sides.
You can't put them at the bottom of the ramp to 4-5 or in the tunnel to P1-3 as there'd only be space for one gate each way (assume you'd need a wide gate), and even if there were two each way you're creating a serious choke point in the rush hour - and in any case I'm suspicious that no matter how many gates there are (I can't imagine more than about 4/5), people will get off trains on P4-5 and end up backing up the ramp. I don't think that's safe at all. Disabled access to the P4-5 lift would need to be accounted for as well.
Also there's the matter that the famous buffet bar is on P4 , and gates would possibly cause access issues for that - I expect the proprietors would have a problem with that, as would people wanting to access the pub.
There is also a wooden gate on P4 (right at the top of P5 in fact) that takes you to the top of a side road leading to the station car park (potential loophole to skip the barrier there with very easy access to services stabled in P5 - good for free rides to Ashton) and some benches belonging to the buffet bar where drinkers are sometimes found outside - alcohol is not permitted on the platforms so I imagine this area also acts as the pub smoking area sometimes. There is a double door into the pub's wooden conservatory that isn't on the platform but I'm not sure if it gets used, if not then the gate would have to stay open. A lot of people use that gate and the side road as an exit to the station.
I don't think you can easily fit barriers to Stalybridge safely, effectively and at a reasonable cost.