Given that London is a major international tourist destination, and
having noticed many tourists staring in bewilderment at the line
diagrams in the trains, I think it's likely that many passengers do
appreciate being told the next station name in advance. There are many
examples of over-provision in announcements, but this isn't one of them.

But if you're going somewhere, do you just get on a train and hope
someone will announce where you've got to get off? Whenever I've been
somewhere I've researched in a guide book or online to find the
nearest station. It's rather like announcing where you can change for
other lines, surely you'd plan your journey beforehand and work out
yourself where you've got to change.