Fire Emblem: Awakening has some interesting balance choices. All such games do, but let's go ahead and use Awakening as an example.
The weird thing about tactical RPGs is that they are balanced very similarly to fighting games. That is, there's often characters who are easy to pick up and play well, but those characters frequently start to have a rough time in a more competitive environment. It's not that they're simply weaker: it's that strength and weakness varies depending on the level of difficulty you're facing, or the level of your enemies.
For example, in Awakening there is a character named "Donnel". Like all the Fire Emblem characters, he's a 90s stereotype, in this case of a pig farming hick. Literally, he wears a pot on his head and talks about pig farming all the time. His special characteristic is that his stat growth is significantly better than the other characters.
It only takes a few levels for him to catch up to the others, and then he basically leaps ahead and becomes an invulnerable killing machine. He's so strong he can effortlessly solo basically any story map. Which, of course, means he gets experience faster than others and gets further ahead.
However, to "balance" him, the devs gave him low stat caps. In the beginning of the game, you can be forgiven for not even realizing stat caps exist. And to an ordinary player at ordinary difficulty, stat caps are unlikely to matter much. They only matter when you start to take on challenge maps, or play on Lunatic mode.
In Lunatic+ mode, the ultra mode beyond Lunatic, Donnel is restricted to more or less the role of "wall", and even then he's easily outclassed by defense specialists. This is because Donnel's class choices are primarily melee assault classes, so he doesn't get any of the advanced defense or ranged offence options that are so critical in Lunatic+ mode. Even if he did get them, his skill stat cap is dangerously low, so they won't fire as often as you'd like.
The classes themselves actually have different usefulness depending on difficulty. Below Lunatic mode, archers and snipers aren't really very useful. You can use them, they're not worthless, but a mage can easily do all the things they can. They have a few small advantages - they can have an extra tile of range, they can learn "bow slayer"... but those advantages aren't really very important compared to their disadvantages.
In Lunatic+ mode, it's probably not possible to beat the game without relying heavily on long-range snipers with bow slayer. The enemies have too many cheeseball, cheaty counters, and melee combatants will get annihilated if they engage. There are some ways to make dark mages useful as well... but default mages? In Lunatic+ mode, they have a rough time of it.
I don't know how much of this is choice and how much is circumstance. When the developers created the game, they obviously created Donnel to be an early peaking character... but his peak is quite high and I'm reasonably sure he could solo the last level in normal story mode difficulty. So his "early peak" is the same as most other character's end of game state - they could theoretically keep climbing, but the game is over. Did the designers intend to leave his peak so high?
Did the developers intend for archers to be slightly underpowered in normal play? It seems likely, because the main archer is a prancing ladies' man who doesn't feel like he'd be very effective on the battlefield.
Balancing is hard, I guess.