Bearing in mind the proximity of the M56 and the HS2 alignment, I doubt there would be any room left for a northward curve anyway.
Study undertaken; in 2000/2001 - "Western Link North Chord", for sSRA.
It does fit, but it is very slow and costly and we struggled to identify any demand (at the time). A Metrolink link from Alty to Airport via Hale and Hale Barns is a much more attractive proposition from a patronage point of view and was debated (a while ago) as the alternative to looping the Airport line back on itself.
The so-called Western Link gives you a direct route to Chester and North Wales, the opportunity for a western station at the airport and even a shuttle MIA - John Lennon, if only someone would design a link at the JL end ... All, that said, we're a way off seeing the temporary wall at the end of MIA p1 coming down just yet!
--- old post above --- --- new post below ---
The Northern Hub document does state they'll be capacity improvements around the Slade Lane Junction area but doesn't expand on how that will be achieved.
Almost certain to be delivered, wearing a false moustache, as part of the imminent re-signalling of Manchester Piccadilly (which may or may not also include elements of remodelling)