I've never played a FE game but have always wanted to. I'm curious, what are some differences?
Kinda difficult to explain the differences since most of my experiences with tactical RPGs comes from FE and FFT is the only one I've played that's different
and my playthrough of it was a couple of years ago.
In most Fire Emblem games you don't have random encounters or even an over world map. You have a map that visualizes the locations to put everything into context and in between maps you get the current happenings in the world as well as an explanation why you're fighting Duke X or Earl Y who is allied with Empire Z in this next map. Stuff like that. The battles themselves (or chapters) are usually a bit on the bigger side compared to FFT. You have units like cavalry on horseback or pegasus riders who can fly. Riding and flying dramatically increases how far a unit can move in their turn and the later can stay on spots like mountains or castle walls that other units can't stand on.
That said, most of the modern FE games have some kind of map that you can replay without continuing the story to level and ability grind. Instead of jobs you have classes. Many of them have some kind of gimmick (mages having the equivalent of black magic, healing classes the equivalent of white magic, cavalry can ride on horseback, generals or knights wear heavy armour making them far more tanky at the cost of mobility, archers get to attack from two spaces away and if the enemy uses swords, lances or axes usually can't be attacked in their own turn).
The biggest difference is probably the way combat works. In FFT each unit has its own speed stat which determines the turn order. In FE you have phases, where each of your units gets to do an action, then each of the enemy's, then yours again and so on. The actual fighting is basically a stat-based coin toss. If you attack an enemy they'll be able to counter attack at the same time. Say you have two sword fighters, then your unit attacks and if the enemy survives they hit back. The unit's speed stat can influence how often you can attack, for example you might get to hit the enemy once, they hit back, but then you hit a second time. Most of the games use a rock-paper-scissors system with swords, lances and axes, so you have to choose which enemy unit should be attacked by which of your fighters.
When attacking an enemy you get a preview that approximates how much health the enemy and your unit will probably have after the fight, what the hit chance is (since you can miss) and what the crit chance is. That's what I mean with "probably" because it could be that the enemy is supposed to be left with 10 HP, but you crit or activate a chance-based offensive ability of your unit which outright kills the enemy.
Debuffs like poison appear from time to time, but aren't really important mechanics. Usually the affected units lose a bit of health at the beginning of the phase. In actual story maps the general idea is to position your units in a way where they won't get overwhelmed by enemies, while at the same time you try to get the most effective units to the enemies you can get killed in a round. There are sometimes gimmick maps where specific characters are trapped or ambushed and have to escape while somehow trying to survive. Or you have to save villagers or some other kind of NPC. The maps themselves can be quite short (around 10 minutes) to quite long (45 to 60 minutes, depending on your luck). The fourth game (which is rumoured to be the next one to be remade and originally only released in Japan on the SNES) has enormous maps that take hours to clear, but also "only" 10 chapters.
I'd say the general combat and gameplay is, or at least feels, more fast paced, even if the map might take some time since it's not unusual to bring around 10 to 12 of your units against the enemy's 15 to 20. You often have various gimmicks that help you balance the fights.
This probably borders on incoherent rambling lol. I hope this makes a bit of sense and I'm sure that if I missed anything important or remembered something wrong people will chime in to correct me.
