Public transport in Liverpool is chaotic. It could definitely benefit from a tram system. Hell I even think there's a business case for a new elevated metro following close to the Overhead Railway route.
The old dock system up by Herculaneum is full of houses and poorly served by public transport. There's only really the 500 bus that runs along the dockside road, and Brunswick station isn't necessarily handy for everyone. It's perfect for an elevated metro with stops relatively close together. Being raised, it wouldn't interfere with the road system, and would be a quick and convenient way into the city centre. It could descend to street level around Stanley Dock to serve the Vauxhall area, with maybe a terminus and depot located near to Sandhills.
But then as I said in the Merseyrail thread, it's taken them 50 years to build Headbolt Lane station. And Southparkway was 30 years late and built in the wrong place. The city is run by cabbages.