Before, I talked about how Fire Emblem made a simple battle system complex by having many different weapons, but melee and magical. But really, that was just the start of it all.
Part of the beautiful complexity of Fire Emblem is that each weapon has a strength and weakness in regards to other weapons. Swords are great against axes, while they are weak against lances. Magic has simliar properties. And yet, it doesn't stop there. As there are both winged, mounted, and foot units, each has weapons made especially to hurt them. Sending a unit towards a unit with such a weapon will spell death almost always.
How you build your team is crucial because of this, and yet, it's never overwhelming. For as long as you think tactically, which is the point, and have a clear idea of what's ahead, which you almost always do, you'll be ok. Balancing gameplay is always tough, and even Fire Emblem has stumbled at times, but over the years it's gotten it's formula refined to a near perfect degree, and it's because of that that I continue to enjoy playing this game.