Neonchameleon
Legend
Natural explorer was a good idea terribly implimented. Giving rangers abilities based on their favoured terrain was a good idea. But where it went wrong was that it gave them abilities in that terrain rather than transferrable abilities they learned from the terrain but could use anywhere.
So for example a mountain specialist in the 2014 PHB got a collection of abilities like "tracks better on a mountain" and "forages better on a mountain". What they should have gained was abilities like a climb speed, expertise in athletics, and the ability to easily guide people in climbing because as a mountain ranger they spend a lot of time (a) climbing and (b) doing mountain rescue. But these abilities apply anywhere, so the expert mountain climber can also climb buildings pretty easily.
So for example a mountain specialist in the 2014 PHB got a collection of abilities like "tracks better on a mountain" and "forages better on a mountain". What they should have gained was abilities like a climb speed, expertise in athletics, and the ability to easily guide people in climbing because as a mountain ranger they spend a lot of time (a) climbing and (b) doing mountain rescue. But these abilities apply anywhere, so the expert mountain climber can also climb buildings pretty easily.