ok, so always been interested in very definitely urban metro-style railways, particularly those in the north of England. So here's some expansion ideas.
Merseyrail
Ormskirk-Preston
Kirkby-Wigan Wallgate
Kirkby-Bootle New Strand
Bidston-Wrexham Central
West Kirkby-Hooton via Heswall & Neston (Wirral Loop)
Ellesmere Port-Runcorn North
Hunts Cross-Bootle New Strand/Aintree (Outer Circle)
Albert Dock-Sandhills via Edge Hill (Inner Circle)
Metrolink
Radcliffe-Bolton
Eccles-Leigh
Eccles-Bolton
Eccles-Wigan
St Werbergh's Road-Fallowfield
Bolton-Bury
Tyne & Wear Metro
Tyne Dock-East Boldon (South Shields-Sunderland)
Pelaw-Durham via Washington
South Hylton-Shiney Row (Sunderland-Durham)
Columbia-Chester le Street
Manors-Percy Main via St Anthonys
Northumberland Park-Newbiggin by the Sea/Blyth/Morpeth
New Hartley-Monkseaton (Blyth/Newbiggin/Morpeth-North Shields)
Airport-Ponteland
Gateshead-Wylam Bridge (coupled with reopening Central-Wylam as heavy rail)
I know very little about the Metro System in the North East, but I have strong opinions about the expansion of both Merseyrail and Metrolink. Here are my views:-
Merseyrail.
Ormskirk-Preston
I doubt this is a good idea. Yes extend from Ormskirk to Burscough Bridge, via the reopened Burscough South Curve. Reopening the north curve will enable a Preston to Southport service which would be of greater value.
Kirkby-Wigan Wallgate
This should be done, as soon as possible in my opinion
Kirkby-Bootle New Strand
This is also a good idea and would be very beneficial.
Bidston-Wrexham Central
Again this should be done as soon as possible.
West Kirkby-Hooton via Heswall & Neston (Wirral Loop)
This is a very impractical idea, the route is now mainly a footpath/bridlepath. The line has been closed for years and I believe that the trackbed has been built on in West Kirby.
Ellesmere Port-Runcorn North
Ellesmere Port to Hooton, Yes. To Runcorn very unlikely.
Hunts Cross-Bootle New Strand/Aintree (Outer Circle)
Albert Dock-Sandhills via Edge Hill (Inner Circle)
Both these line are very unlikely, although an extension from Hunts Cross to Warrington might be a practical consideration.
Metrolink.
Radcliffe-Bolton
This route was supposed to be included in the Picc-Vicc Line plans, but the route through Radcliffe has been grratly compromised and built upon. Although it would be an excellent add-on to the Metrolink system, shortsightedness has made it almost impossible to be done.
Eccles-Leigh
This also would be a good idea. Leigh NEEDS to be rail conected to Manchester. This would be a far better means of doing this than the daft 'Busway' idea that is being floated at this time. If is is routed properly, then the Towns of Tyldesly, Mosley Common and Worsley would really benefit with a Metrolink service into central Manchester.
Eccles-Bolton
Even if you routed this via the old LNWR route, which has been blocked from about Farnworth into Bolton it would not actually benefit people from Bolton. You can be in Manchester in less than 20 minutes by heavy rail. If you went up the main Bolton to Manchester Road A666, which is very busy in the 'rush hour', trams would not be much better than the current bus service which can take as long as an hour. I know because I have been on them from time to time. Not a practical addition.
Eccles-Wigan
Again not a practical addition, the heavy rail service via both Bolton & Atherton, could be improved much cheaper and the service increased much quicker than building a seperate Tram route.
St Werbergh's Road-Fallowfield
Possible this might work if you continued past Fallowfield and terminated the trams at either Guide Bridge, to extend them through Hyde and terminated them at Marple Rose Hill. This would release cappacity on heavy rail services running into Piccadilly from Chinley & Sheffield.
Bolton-Bury
Although the old rail route is relatively unblocked, I don't really see any benefit to doing this.
In summing up there are some very good ideas, which in any sensable, well run country would have already been done, but here in Great Britain no chance sadly. Some of the others are pipe dreams, which are never likely to happen. What we need to do is to push for those which have a good chance to succeed, and hopefully they will happen one day.
Don't hold your breath though.