I guess I think of Orienteering as a race not a pass time and a navigation based race is a little pointless if you know the way. It's then just a fell run.
It is a race at a competitive level. And a lot of fun, too.
Whilst there are training things that can be done on repeat visits, I agree that going to the same place with the same controls again and again is not brilliant. But there are lots of POCs, so you can visit ones you've never been to before.
There are plenty of people who like to go out for a walk with a little nav interest thrown in.
And, one of the biggest things I'm working on as chairman of my county orienteering club, is that they are great for introducing newcomers.
Oh, and we aren't allowed to race at the moment, but we are allowed POCs.