It should be a 5k - 6k arena.
The jump from the 2k Apollo to the 20k M.E.N. and 23k CO-OP is too massive leap for many bands trying to bridge that gap. Liverpool has the same issue with their smaller venues then the large arena (M&S).
We'd fit in perfectly as that bridging gap in the NW.
Gigs, Comedy, Boxing, Theatre, Conventions.
M6, M61, M65, various Rail links already there for those who need to travel. A decent local age demographic and of course, it's now a bona fide student city.
Lastly, we have plenty of hotels in the area.
7 years to get this done, with or without private money.
I'll even suggest a name - The Guild Arena.