I cannot describe to you just how much easier Fates on Lunatic would have been if I had these in that game. Obviously you would need to have some kind of default weapon for this to work (either that or make the boosts so good you don't need to attack? but that sounds OP in its own way) but even with other games if you had an option in inventory management to take a more defensive stance during the enemy phase it would mean so much for how you set up your turns.
It's a shame GBA hacks have a problem with pulling this off since you can't balance out def/res boosts by adding a speed penalty though, due to how the games weren't designed to consider any items causing stat nerfs. (names would get annoying too to keep it within the weapon system, like "Slvr Shld w/ B" to mean "Silver shield with bow" for archers...not even sure if that fits within the display limit, either.)
Summons that actually matter
Remember FE8 with its hilariously situational phantoms? This game wasn't having any of that. Invoke had to be one of the most useful things in the game (and basically the only thing Celica's team had over Alm's team prior to Act 4 tbh) for keeping your not exactly tanky units alive and useful. A lot of the time in FE games the actual competence of the enemy units drops significantly once you reach mid-lategame and beyond, but if the developers did feel like having the enemies keep up with you or even be stronger, having cannon fodder to protect your troops would give me a hell of a lot more confidence to play it on classic mode. (Lunatic Classic on Fates was just...ugh. Not something I'd want to do again.)
Extra range bows
Now as stupid as I think it is that bows have point blank attack range in this game (I don't even want enemies that close to my archers even in FE15 anyway) it's well known that archers in FE games tend to be underwhelming units, and a big part of that has to do with mages just being way too much better than them most of the time. Magic gets away with 1-2 range on nearly all the tomes, resistance stats aren't very likely to be high on enemy teams, you can straight up carry your superlongrange options like Bolting whereas archers need to have a vehicle or a fixed machine on the map to do the same thing, and having worse durability against enemies isn't even that much of a con in comparison to being straight up unable to counterattack.
I'm pretty sure most archers throughout the series could at least get away with making almost every bow 2-3 range or something, making the longbows 2-4 or 2-5 range while they're at it. Even as someone who does use bows in most FE games that's usually a matter of handaxe/javelin not having enough might to finish something off or to hit something three spaces away. We could also re-introduce crossbows for other units (weapons with fixed attack power) that are primarily melee-focused so that the bow-exclusive units get away with being the only ones to have bows that are viable for the whole game. They just deserve to have some kind of non-situational edge over mages, you know?
I think if I am going to have archers which have the ability to counterattack at 1 range I'd rather they just have a dagger they default to once they're that close to the enemy. That way they don't get all the stat bonuses of their weapon (and don't look kind of dumb bothering to shoot from so close) but still have something they can do about it when they've become forced to fight that close.
That's all I have to say and while there are a number of other fun things this game does that others don't I personally feel like that only functions the way it should in FE15 because its system is designed to support it. Do you think anything else this weirdo of the franchise has warrants being in other FE titles?