Msybe I'm just being snarky, but some of the promotion choices are ridiculous. I had my warrior beat off an attack while on a barren mountain surrounded by other mountains and desert and my choices for promotion were:
1) Unit strength; or
2) Woodland.
If your unit is eligible for promotion based on combat (not leaders), the promotions available should bear resemblance to that combat. If you fought in mountains, the mountaineer promotion should be available, along with the more general ones, i.e., medic or unit strength. City defense or woodland, in such a case, should not be available.
Similarly, if you beat an Axeman and got a promotion as a result, you should not be able to choose a promotion which gives your unit increased effectiveness against archery, gunpowder, mounted, or siege units.