I believe the SMN/SCH incident is what really got SE to not go beyond their iconic attack methods and simplified path. It probably really stressed the developers how they could separate SMN and SCH gameplay and stats during the early years of 2.0 and 3.0.
Sword job is not really a issue itself but that most sword Jobs are going into Tank jobs because of maybe creativity reasons involving Swords being very easy to fit into a Tank Job Role. For DPS role a 2nd Sword job as a option rather than ONLY Samurai is something people want. We're also missing the Melee Magic DPS type job which would fit Mystic knight/Spellblade Job as that job has a long history of Magic infused melee sword attacks so it fits into people's desire for both a sword DPS Job and a Melee Magic DPS Job.
We hav currently...
Tank Jobs
Paladin - the Classic Sword and Shield
Dark knight - Greatsword and Darkness Magic
Gunbreaker - the Gunblade/Tech Sword
DPS Job
Samurai - Katana Melee range
Red Mage - Rapier that practically does not exist because it is used mostly as a staff 90% of the time for Range Magic attacks.
Chemist is still fantasy themed thanks to Alchemist with the Job having potential of the lore being about Alchemist that discovered and decided to utilize the Alchemy type chemicals for combat use as Combat medics for people who lack talent in Healing Magic but still can play a role has healers for people. They can even link it to Garlean theme if the decide to use the Chemist Job storyline to expand on the history of Black Rose chemical weapon and the other scientist involved with the creation of Black Rose.