SE can change existing weapon ( dagger on thief, langsword on pladin, shortsword/gladius on gladiator) and introduce new one for new job.

For Skill/ability of new job, in my opinion, is better Traits

For Expample : i have GLD 30 and CON 20 now i'm able to unlock Paladin (Longsword/Shield) at rank 20 i'll unlock, like normal ability, a Traits for increase damange versus undead mob type, at rank 30 a Taits to improved guard for given extra armor on party member when i'll use Guard ability, etc...