Fire Emblem: Illuminated

What makes this incredible is that on top the maps having a lot of cool gimmicks and playing with a lot of cool setpieces it also a phenomenal narrative. The lead characters relationship lands but the supporting cast all have a solid narrative beats that make the whole party have value. Limiting the party to 16 units is rough for iron man runs but I feel if you're willing to accept playing this without doing so it's possibly one of if not the best romhacks for hte game you can find.