I feel the terrain features should be more general useful.
I.e.
After a long rest, chose one of the following and gain it's benefit until you next long rest. Allies who took the long rest with you also gain a benefit while they are within 200' of you.
Forest: you ignore difficult terrain. You and your allies are not slowed by marching.
Sea: you gain a swim speed. Your allies gain advantage when making swimming checks.
Plains: +5 speed. You and your allies can see up to a mile away.
Mountain: you gain a climb speed. Your allies gain advantage when making climb checks.
Also, just give Rangers expertise in tracking. Any kind, anywhere.