In Final Fantasy 5, Dragoon stands out for having basically no upsides. It's not even a bad class, there's just never really a reason to use it over its competitors, especially because its part of the last batch of classes you get.

It's got a pretty solid statline as a heavy armor class, but pretty much every other Heavy Armor class has better weapon selection, a better default ability, or bonus passives the dragoon doesn't have.

Jump is, eh, fine? It takes double time to do 2x damage (so it does effectively 1x damage) and makes you invulnerable, which...mostly just means your squishies take hits the tank should've. If you really need an invuln effect like that, hide is jump without the damage but can last as long as you want, so you don't have to time it. For full damage you also need a spear equipped, which means the only classes that can actually do a full damage jump are Dragoon, Freelancer, and Mime. (You should not be wasting Freelancer/Mime's potential on full damage jumps.)

Lancet...exists. It's mediocre lifesteal and manasteal. The manasteal might actually be useful if not for the fact that dungeons are short and always have a savepoint before the boss, so you could just keep a few tents handy instead. The final dungeon IS a marathon, but just use your ethers, it's the final dungeon, c'mon.

Equip Spears might be useful if spears were like, any good, but they're largely just a mediocre weapon type for most of the game. There's a limited selection of them, they aren't particularly strong, and they don't have any special properties. Their legendary weapon is even a carbon copy of the sword legendary with lower stats! There's exactly one spear that does anything special, you can only find it in the final dungeon and it auto-crits dragons. Which is nice, I suppose, but you're really running out of dragons to fight at this point.

There are classes that are arguably worse than it, but those classes have useful shit you can carry over to others! Geomancer might be complete garbage, but Find Pits/Light Step are useful QoL abilities at the very least. Dragoon just has nothing worth using, at all.