Okay so i played up through 5x, some thoughts.
First of all, it doesn’t seem like things are much harder? The skills on the player’s side are quite powerful (canto+ on every mounted unit?! I guess this will balance out once you start facing horse units but…) so even if you did up enemies’ stats, it’s largely nullified by the increased power on the player’s side. (Now granted i played on normal and should probably been on hard, but i didn’t know how much you had changed.)
The skills weren’t as distracting here as some other games i’ve seen, maybe because the party is quite small to start with. Still ends ups being a lot of busy work looking for who has what skill and what it does, though…
I don’t think Eirika needs Paragon given she’s forced into the party so much and (unless you change this) will ram her cap long before she can promote. She hit level 7 in chapter 1 (!) and was level 13 when i left off. She’s also naturally quite fast enough that i don’t think Darting Blow helps her much.
(It also feels like Ephraim’s skills are just better than Eirika’s? Ephraim really doesn’t need any more help to be the better unit between the two.)
I hate Counter being so common - it’s not “hard”, it’s “tedious”. It encourages you to just sit next to enemies instead of attacking them, so they’ll attack first, eat some damage, and be killable next turn (or in two turns, or…) Please reconsider this being a class skill, especially for both fighters and archers.
The gauntlets are fun.If you want a simple icon for them…?
(Feel free to edit, of course.)
Ross coming at a higher level is nice, he’s actually worth using now, but is it necessary to give him a trainee seal that sells for 10k? I don’t know if Ross’ contribution is worth more than the ability to buy 9 elixir charges since you’ll quickly have to start benching people anyway. I’d at least make the seal worth like 1k at most so it’s less tempting to bench Ross for it.
Colm doesn’t seem able to steal despite having the skill for it, i tried with several units in his joining chapter.
(I do appreciate there being more sword users on that map for the lance users to fight, but the middle merc didn’t want to move, making it easy to pick them off.)
Even with their skill, monsters are very weak. And Artur coming with Slayer for free is hilariously strong.
Unfortunately i can’t really comment on how to build satisfying difficulty, it’s not a thing i’ve ever practiced. But enemy bases should probably be increased in general, particularly monsters. You might also want to tweak stat-altering skills; they’re balanced for Fateswakening with much higher stat caps. Artur passively giving +4 speed to adjacent allies or Neimi being able to debuff for -6 def is kind of nuts here - try maybe halving the effect of skills like that?