List of heavy armored dragoons in other FFs
Ricard (FF2)
Dragoon job (FF3)
Kain (FF4)
Dragoon job (FF5)
Dragoon job (FF11)
Lightning garb (Lightning Returns)
Dragoon job (FF14)
Bangaa-exclusive job (FFTA & FFTA2)
Barbara & Dragoon job (Dimensions)

FF games where they are not
Edgar/Mog (FF6 - yes, a stretch, but both can equip spears and the accessory which gives access to jump does extra damage if the user has a spear)
Cid Highwind (FF7)
Freya (FF9)
Kihmari (FF10 - giving this one as well because lancet reappears as a Dragoon ability in 11 and his first overdrive is jump)

So yeah, Dragoon is iconically a heavily armored class.

Plus the dragoons of real life from which they took their name were armored infantry who ride into battle on horseback but fight on foot with blunderbusses called "dragons".