I actually don't think HHM is THAT difficult either. But, then again, I've played Fire Emblem Sword of Seals. Here's an enemy stat sample from towards the end of the game (on hard mode)
Lv. 20 Mercenary 43 HP 17 STR 20 SKL 18 SPD 10 LUCK 10 DEF 5 RES
Yeah, and that's an unpromoted enemy.