One thing I've noticed Fire Emblem is exceedingly hesitant about throughout its entire history is creating classes of certain movement types with access to magic. It seems to go, in order of most to least likely: foot, cavalry, flying, armored. The lattermost, to my knowledge, has never seen a playable magic-using class in any mainline Fire Emblem game.
Even in Three Houses, which supposedly was all about breaking the weapon-class relationship and allowing units to use basically anything, they made a very conspicuous exception for magic. Flying mages weren't available until the DLC, and armored mages still aren't available at all.
To this day, the only way to get an armored tome user outside of Heroes is temporarily, via engaging with a tome-using Emblem while in an armored class. Micaiah means staff-armors have a bit more luck, however.
And I have to ask: is there any sensible reason behind this? For the combo to have eluded mainline use for so long, you've gotta figure they have some reason for it at this point. But I can't for the life of me figure out what it is. I get that most magic-users tend to be fragile, but the cavalry ones in particular have often received more than enough defense to see action on enemy-phase, so I can't imagine armored mages would be that devastating in the player's hands. Especially since they're in the running for worst class in the series so far.
Thoughts?