Nohr's path is actually paying homage to how the gameplay of any older Fire Emblem game that isn't named Gaiden, Sacred Stones and Awakening is. Players here are sticking on the rails of the plot without breaks and are stuck with more limited resources in addition to further mission completion requirements. The path of Hoshido is definitely more lenient than the other path, unless you don't take advantage of grinding and a lot of resources.
Maybe Nohr's path isn't difficult for Hamayama in the first two chapters of Nohr's path because his units have their stats properly managed before hitting those chapters. Then again, he isn't tackling on the harder difficulties.
From what I've seen so far, the Lunatic difficulty curve seems to be well-managed this time around. I couldn't be sure as I haven't touched on that difficulty in Awakening, so I had to search in Internet for that.
Someone on GameFAQs who began playing at Lunatic difficulty posted a thread. One was saying that the Nohr campaign raises the difficulty pretty high and quickly after choosing it in the sixth chapter. Another says that the enemy stats aren't ridiculously high and the same turn reinforcements are nowhere to be found, at least in an early-game playthrough.
I'm definitely more interested in the game now that it's been said to be quite different than what we're seeing.
