Just beat Hoshido last night, and starting Nohr now. Honestly, I don't think grinding was necessary to add in Hoshido -- I never touched it, and all of my units were at the right level for endgame (~Lvl 15, promoted once base class reached lvl 20). It's definitely harder than Awakening. Dodging is much less frequent than in past games as most enemies always had about a 70-80% of hitting you, and by end game they hit HARD. So if you're playing on classic, you have to really strategize if you don't want your units dying left and right. Funnily enough, the children chapters were harder than the endgame chapters (enemies had higher stats here), but those offered a really nice challenge. Map design was better than I expected, especially near the the endgame, though I am VERY disappointed in Chapter 26 -- it's the one where you face off against Marx, but he's accessible from your starting point, so I beat the chapter in one turn. :P