I've been to all those places mate, apart from Canterbury, and they are beautiful cities with a lot of history and heritage. But none of them house anywhere near the number of grade 1 and 2 listed buildings that Liverpool does. At it's height literally one half of world trade went through our port, and it was the staging post for emigration to what is now the richest country in the world, including nearly half of the Irish population. Americas first sky scrapers were based on Liverpool buildings and Central Park based on the one in Birkenhead.
Liverpool may have come late to the party but don't underestimate it's importance and the imprint it left on the world.