Is Genealogy really such a hard game? Definitely one of the least frustrating due to its save system and I found throwing Forsetti or Sigurd at most of my problems a fair solution. (Or any of the more OP units second generation)
I feel if your idea is to make FE4 more welcoming to western FE players, you should try and use some its core philosophies found in post FE7 and balance what you buff with nerfs. For example, you could nerf the holy weapons to make them more like the GBA titles, where they only give slight buffs instead of bloody insane ones. Just an idea, I personally think there is enjoyment to be had out of FE4's gameplay, not just the story.