I'd support this as I've said before (I would go for a Merseyrail style 15 minute frequency all stations service calling at Mauldeth Road, Burnage, East Didsbury, Gatley and Heald Green) but I wouldn't use 12 as it has no access from the bridge, I'd use 11 instead and move other services that use that to 12.
One thing I've noticed is that TPEs via the Chord are VERY busy including passengers boarding at Vic for Picc. This could be resolved by either including Metrolink travel in all Manchester Stns and via Manchester tickets and making this clear (perhaps use a symbol like the + to denote it), or by removing the TPE Chord services and replacing with a Northern EMU service using EMUs with a standee layout on a shuttle.
Actually, scratch using 11, it could be Airport-Manchester Vic calling at all the Styal Line stations then Picc, Oxford Road, Deansgate and Vic. Extend all stations to Rochdale once that's wired.
That's a fairly horiffic crossing move across the lot somewhere between Deal Street and Miles Platting? It crosses *every* flow from the CLC, Chat Moss, Atherton and Bolton at some point on it's trip round!
I'm fairly sure with every debate like this, sending everything to Man Airport ends up being the least-worst option in terms of conflicts.
I am surprised at quite how popular the Vic-Airport flow actually is...certainly not a 'you can just get the tram instead' level of flow...