Shed as I have said before, "it's full potential" is almost meaningless as it means different things to different people. It's qualitative rather than quantitative. MAN cannot maximise potential throughput as a spoke, it needs a based network carrier, and I don't mean fly(may)be. Since BA can't make money hubbing at MAN that means, honestly, full potential is limited to competing for business as a spoke. Nothing wrong with that in the current trading environment.
Btw the Virgin farce is beyond parody. What were they celebrating? The third decade of ATL-MAN? 😉