I’m still learning and didn’t get much feedback on my current approaches so far so my methods might be very flawed.
My experience is that in terms of Gameplay and Meta → Speed tends to be the most important one because it determines the total maximum of damage that your units can deal to them. If a unit is strong, that’s good. If a unit is fast, it might be capable to deal more damage overall despite having a lower Strength stat. Naturally these units can do the most in one turn. So keeping an eye on this stat was mandatory for me once I realized how powerful it can be.
Second might be Skill since you want to have a fair Hitrate for your player. It can be a bit shaky but should be higher for the players sake imo to make sure he has a good time and that he feels more punished for his own mistakes than blaming it on the RNG (which many players will do anyway). If both the players and enemy hitrates are equally reliable it becomes a fair game. Playing around with the Hitrates of FE6 and looking at the meta of that game showed me how much impact Skill can have on the game.
When these two work that’s good. The rest needs to be adjusted.
Overall the enemies of your game should be designed around the stats of your party. Personally I calculate the bases of all units that are playable up to the certain chapter I’m working on (Bless the average calculation of FE Builder), using something slightly below the base level of the party (or if the character just joined/his level is out of the line being higher/lower than the rest or because it’s a prepromote - the most realistic level he’ll have around that point) and THEN I add all of them together for each stat and finally divide it through the number of characters I took them from - With this I can calculate the Averages of the party. This allows me to see where the characters are good/bad in and how I can influence the meta of the game. It is a good reference to know how the stats of the enemies should look like. And to see which units suck or become too good. Having this noted as a reference is nice. Of course in the end some finetuning will be nessecary. But that’s my personal approach and so far it worked for me.
Basically no matter how the stats/growths of the units look like, as long as I use this, I can make sure to keep everything in a certain range. And when using something a bit smaller (not counting hard mode which will be just about the same/a bit higher stat wise due to bonus levels - or not Idk how I’ll do that yet) I can ensure that the odds of having an unfair matchup becomes less possible.
ANYWAY to get back to the topic. I got inspired from Vision Quest by this but I did notice that it’s more fun for me to have less enemies to fight but giving them better stats to ensure it’ll be challenging. I always try to make it so that the player characters will/can be better overall. But every character should have one or two distinct factors that don’t overlap too good while the rest is either mediocre or bad. For example the lord of the hack I’m working on RN is… pretty good I’d say. He has a good strength stat and can double some enemies. Also he has a Personal Weapon that’s pretty good (which should be factored in as well since you can do lot’s of stuff with these things) and the Galeforce Skill. The latter especially made it clear that we need to be careful to not make him too strong both base and growth wise. We ended up giving him decent stats overall. Nothing too good or bad, the factors I named earlier ensured that he’ll be useful and (importantly) isn’t a burden. But he got bad defense and we nerfed many of his growths after testing.
If you have a fast unit either make its strength okay and the rest nah to mediocre. Or give it good speed and strength but leave skill at a normal level - The defense of the character should be bad but bearable.
A tank should not be too good in both defense stats. Either above average in both or good in one of them. His speed and/or strength should be lower.
If you’re using the normal version of the patch that enables to see growth rates ingame a good indicator for growths are the colours. Keep some of them between red and orange. The majority should be yellow. And there shouldn’t be too much green. But overall, like I said - if you keep track of your units averages you can balance the enemies around it.
In general the units of the current project started mostly with pretty good growths which would later be nerfed or buffed depending on the situation. Buffing growths is easier than nerfing them since if the numbers got lower you need to test if the enemies are still around the same level or too strong.
If you keep enemies and player units balanced, the player units can be whatever you like to do. Giving them stats according to their roles and personality (working with their Skills if you have those) seems to be the best way. When I have units of the same class I do look at the average stats the previous character can have around that point and give the new one stats based on that. One get’s a bit higher the other one a bit less. It’s the same with the growths. If Axe Dude 1 has much defense and HP but less speed and skill, I give Axe dude 2 more speed and skill but less defense and HP. Although at this point I look at it more gameplaywise than personalized to the unit. Unless it’s a character that is supposed to work in a certain way.