Adrian Auer-Hudson, MIMIS wrote:

Terminating Mets at Moorgate would reduce the service to Liverpool
Street.

How far is the Walk from Liverpool Street to Moorgate?

It's not the furthest distance one could ever walk, but it's not the easiest
to follow.

Also the Hammersmith & City and Circle lines have very erratic services at
Liverpool Street - without the Met the trains will overcrowd.