I know that in one of the proposals for the Gap Project there was a "High Level halt" on the embankment North of the bridge which would make access from the MML station very easy....but then there is the disabled access requirement, ticketing, unwanted access etc so I don't know if it is still being considered.
The Mountsorrel Branch dealt with the disabled access requirement well, with the zig-zag ramp access down the embankment to the station site (see below picture). I imagine a similar approach would be used to access the site, which I think was supposed to be between the Cotes Road and MML bridges - in fact concept art shows access ramps in situ. There's enough land at the foot of the embankment for a small amount of parking and perhaps a simple ticket office if they need to provide staff assistance, though I think hopes of platform buildings beyond a simple waiting shelter may be over-optimistic given the narrow nature of the bank they're constructing.
As for ticketing, I imagine it would work on the same basis as other unmanned halts on heritage lines - buy on the train, flag down trains, etc. If they do want to man it, great - I'd love to sit in the ticket office watching the MML between trains all day!
I think the main issue would now be space. The original track design took the station into account back when it was still planned to be a double-track bridge, but I'm unsure of how it would fit into the simplified alignment without needing to be built further north on the line, which would reduce the convenience of being adjacent to the MML. The bridge abutments have a longer approach, too. The net result of all this is that the feasible length of the platform, which was short to begin with (see below concept art) would probably now have to be even shorter to accommodate approach signals for the mainline connection points.
This being said, a simple halt on a single track line may remove these complexities - the above art references a proposed southern terminal for the GCRN which fell by the wayside with the reunification project. The space issues referred to the installation of a run-round loop, which is no longer needed with the gap bridged as trains will be able to do so at Loughborough Central.
Finally, regarding unwanted access and vandalism, I'm hopeful that the station's fairly inaccessible location would deter would-be trespassers. Loughborough Central has gotten off fairly lightly in the past, and it's in the middle of one of Loughborough's dodgier areas. A CCTV presence might be enough to keep it secure. The only real sticking point would be a direct access to the Network Rail station, given it's a station with ticket barriers (they never work, but they're installed nonetheless!)
This is all conjecture, of course. I imagine that upon reunification, building a terminus at 50 Steps Junction and reopening East Leake will be the first priorities in any case.