So the argument Noir proposes against Expert level is that +4 morale gives “more morale than the engine range is capable of supporting meaningfully”. Well, any faction can get +4 morale for any units that are produced in a province with the right religious structure, so you can’t escape that by playing on Hard. However, these units will not have the higher combat power/greater challenge that AI units have on Expert.

Now for the argument that it is an exploit on Expert if I fight units that I know I can defeat, because I will gain valour more quickly than on Hard. If this is indeed the case, then what about AI faction units that fight each other on Expert? Wouldn’t this exploit make the AI units “valour up” more quickly than on Hard as well? Then my units are fighting more powerful AI units than I could hope to meet on Hard. Doesn’t sound like an exploit to me. Besides, when I have set up a battle that I knew I could win, the AI retreated from the province. In battles where the AI cannot retreat and must fight, they already get +8 morale, even on Hard.
I recommend playing on Expert to everyone and remain, humbly, unconvinced.