Each quests (common, uncommon, rare) and events have power level values assigned to reference their potential difficulty levels. The helpful hints on the screen already suggests these values are only for reference and not indicative of whether a player would be able to beat the level or not even if his/her team power does not exceed the value.
Although I am sure these will probably go largely ignored for the first few map levels or even later ones for the long time players who have already cleared the maps, but why not have point values assigned for all the CPU map levels (e.g. non outpost levels) as an indicator for players to use to reference as well? The enemy numbers there show up are random, but the types (and final boss of the level) are the same. I think it should be a fairly easy value to assign and feature to implement.
For example, I find myself kind of struggling on Map Level 20 Map 6 at the moment (either gets killed too quickly, spent way too much battle items, etc.), if I can see where the difficulty number is, I can use that as a reference point to see what power level my team should to be to be able to complete those stages.