There's no easy solution, no. Physical constants at the airport mean it's close to impossible to expand the station. The only other option is to run fewer trains to the airport which is all well and good, but there's precious little capacity to terminate them elsewhere either.
Only solutions are to not terminate so many services there, but to continue them to somewhere else, or for those which do terminate to ace do the same if they have a long time before returning. Wilmslow would be perfect for this, trains could reverse in platform 2, or use the siding if there was something else behind it.
I doubt it would raise as much of a stink if a late running Wilmslow terminator was cut back to MIA either.
TBH I’m shocked this isn’t done given the congestion at MIA. The service on that section of the Styal line is certainly sparse enough to allow it, and would cost nothing in infrastructure enhancements.
