Here would be the resultant job(s) that follow up on the Reaper:
Devilot/Aetherial Warrior/Spectral Knight
The reason I've given the job 3 seperate names is because of a clever idea. A player would have the option of which job they would want to take from the Reaper class, each one having to be unlocked with their relevant quest. Each one would play similar to the Reaper much like how jobs are (from what we've been told) going to be like with other classes (e.g/ gladiator > paladin), being able to utilise the skills of a Reaper along with aquiring job specific skills. However each one would work in a different kind of way and therefore possess seperate types of skills to go with their initial Reaper abilities.
Devilot
The Devilot would advance much stronger as a DD job. The aura buff would change from increases buff and debuff potency to purely increasing overall damage, possibly scaling up to 40% instead of the 20% a Reaper gets. Their buff and debuff skills will still be usable but will only have the base effect of a Reaper, and not benefit from an enhanced aura.
In regards to appearance, the aura of a Devilot would take on a much darker tone to signify that they are designed simply for destruction and damage (no good have shiny pink fluff coming off them when they're meant just to kill stuff). This could be something such as their eye-glow/body-glow taking a much more solid appearance with a dark red/purple hue, and their weapon sparking more and more as the aura increases.
Along with this the characters general appearance could change, possibly to include small bats wings on their head/back, and in the case of miqo'te, have their tail change into a more forked appearance much like a devil. This would give the class a much more unique appearance to it.
In terms of clothing and equipment, a Devilot would stick with the general leather gear, possibly even branching to a more stylised appearance of something a bit 'saucier' like Morrigan from Darkstalkers. Sure it screams 'sex appeal', but usually that's what entices a player to play them anywaysAs for weaponry, a Devilot would focus more on use of an aetherial scythe to increase it's general damage output.
Aetherial Warrior
The aetherial warrior would focus much more on their support role in combat. Their aura would increase the buff and debuff potency of Reaper abilities much more, and the job itself would gain even more buff and debuff skills such as more DoT's, some binding, blind, and interrupt abilities, stronger and more potent leech skills and more powerfull stat transferrals such as MP, attack and defence.
For appearance, the aetherial warriors aura would change to something with a more 'parasitic' appearance, maybe with aetherial arms or ripples reaching out from the glow to show the class is designed as a sort of 'leech', similar to something like this.
The clothing again would stay much the same as a Reaper, mostly focussing on leather equipment but possibly with a more torn or ripped appearance like this. As for weaponry, the Aetherial Warrior would focus more on the use of the two aetherial blades, however the blades appearance would change slightly to make them look less solid, perhaps moving or swaying like a parasites antennae.
Spectral Knight
The spectral Knight would be a much larger change from a Reaper, as it would be designed to be a tank. It's self-buffing abilities (such as leeching defence) would be enhanced more potently than what an Aetherial warrior could do, however it's debuffing abilities and MP and HP transfer abilities would lessen so as to not make the job better than an Aetherial Warrior when it came to support. The abilities this job would gain would be more focused around enmity gain and self-survival. Their damage output would stay pretty much the same as a Reapers, since a tank doesn't really require a great deal of damage, only to be able to hold and survive against an enemy.
For appearance the Spectral Knight's aura would be all-encompassing, causing the character to become mildly translucent with small ripples flowing from them. This would give them something of a ghostly appearance which would fit with their ability to mitigate and evade incoming damage.
The clothing would change from leather to chainmail and plate so as to allow them more defence and +vit stats. However seperate from a Gladiator or Paladin, a Spectral Knight's armour would look more broken or ancient, enhancing their 'ghostly apparition' theme, kind of like this. For weaponry they would wield a single aetherial blade, possibly with the choice of axes or maces also, but in their off-hand they would wield an aetherial shield to give them a better appearance as a tank job.