The thing is a minority share will not work for the Glazers although they talk about it. If they sold off 20/30/40% of their shares, then it probably still won't give them enough to do what needs to be done to grow revenue, all they have now is a less control and now an investor who will push pressure on them to ensure they get a decent level of returns.
Super League is a non starter, especially with these new rules apprently coming in. The improved sponsorship, well i think what happened with Chevvy and now TeamViewer will see them struggle to get headline sponsors of that level once again, even the kit deal is nearlly ran it's course and they would already be talking to Nike/Adidas etc to gauge what they are willing to pay.
I personally think Glazers know they have milked the cow as much as they can. The timing of this is obvious, they would of got the plans + costs from the Master Planners appointed last year, they would be looking at the shirt sponsors (as they agreed to let TeamViewer out the deal) and the price companies are willing to pay, same for the kit deal, obviously their grand Super League idea went in the bin so now they have nothing to grow the club with.