Let's hope we have a Regional UK Powerhouse rather than just a Northern (Manchester) Powerhouse.
But it isn't the 'Northern (Manchester) Powerhouse'. It is the Northern Powerhouse, and it promotes the integration of major cities across the North. The benefits envisaged if the project ever reaches maturity (in light of recent events) will be felt across the North from Liverpool along the M62 corridor to Hull and up the East Coast to Newcastle.
The concept has also been rolled out to other English regions. You may wish to google the 'Midlands Engine' and the 'Anglian Powerhouse' (Norfolk, Suffolk and Cambridgeshire). For self-evident reasons Scotland, Wales and NI already have political structures which serve the same purpose.
Your wish has already been fulfilled!