If there were more enemies traversing would be a shore. The game is an action game where long combos are preffered so the more enemies the longer it takes to kill them all the more the pacing goes to the toilet.
See?
That doesn't have to be true. If you design the game so that the player's abilities make it easier and quicker to take down previous area enemies, then you can achieve a quicker rate of exploration for past areas, while retaining higher difficulty for the new areas. Typically this is most successful when the majority enemy introduced in the current area, is best handled with the upgrade found in the current area. It is what you should be striving to do.
You can layer this effect if you want a mismatch of combat and platforming ability progression. The easiest way is simply to have a leveling system on the side, while having platforming and mobility upgrades done by items. The harder is progressing the combat and platforming abilities side by side, making sure they don't get too far ahead of each other in proportion, and the abilities don't stack to imbalanced spikes of power increase.
Though, I don't find it much harder to balance using all scripted powerups on both sides of the progression. It's not done as much for fear lesser players will get discouraged, and it takes only a little more thinking on balance pure scripted powerups.
Lords of Shadow kind of goes for a middle road, and one I generally approve of, where your combat is split up, with some experience granting you new abilities, and key upgrades relegated to scripted times. Where Lords of Shadow, and seemingly Mirror of Fate, are doing it wrong are that the enemies have so much HP, and the upgraded moves don't bridge the gap (plus the moves cannot be used due to length of setup time / imbalanced hit-stun), there by reduce the number of enemies to 'fix' the problem, but create other problems as a result (ie. empty halls).
See? No Miyamoto required.