Clearly there are a number of ticket offices, particularly at quieter suburban stations, where it serves little useful purpose for someone to sit around behind a pane of glass, waiting for Godot! Sadly, but realistically, there is only one direction for such ticket offices - closure or very limited opening hours. Staff working at such ticket offices are probably best served being offered voluntary redundancy or else reallocation to other roles in the industry.
However there are plenty more stations where a staff presence is justified, but again having someone stuck behind a window is not very efficient. Virgin Trains (West Coast) went in this direction a few years ago when they rolled out their new Ticket Issuing System (TIS), Avocet, which could be used on a tablet so as to allow staff to wonder around near the ticket machines, helping people with any complex queries. Not much seemed to become of this, and there are still ordinary ticket offices at all their stations. But this is the direction in which I would see the staff presence at larger/busier stations heading - having staff moved to multi-purpose roles, where they can undertake "ticket selling assistance", dispatch, keeping stations in good order and perhaps occasionally assisting with revenue blocks as well.
The threats of balloting from the unions are not particularly helpful, and in my view they would serve their members better by trying to ensure the best possible outcome of any changes, including a guarantee of no compulsory redundancies (which, given that the railway is still recruiting left right and centre, should not be too onerous).