I know it's been a while since the reveal, but I haven't been able to keep Reaper out of my mind despite being a healer main since ARR. From the lore to the mechanics, as well as whether it'll be a selfish or selfless DPS I've been wondering. So this has been my own imaginings of how the reaper rotation might be.
Considering the aesthetics, I figured that Reaper would share some mechanics with DRK, even if it was on a surface level. So MP would be a major consideration during the rotation, not just the exclusive gauge.
The combo would start off with the usual 1 2 3, with an alternate combo for a damage buff and maybe a DoT to go with it.
The DPS combo though, would also recover MP. Maybe 2k for the 2nd hit, and another 3K for the third.
In turn, the main skill to go with all that would be an oGCD that consumes a decent amount of MP. Maybe 3-4k per use. This will be the summon avatar skill, to do a single hit whenever you want in melee.
The avatar's attack would fill up the job gauge, maybe 10/200 per hit.
Possession costs 150, or maybe a bit more. But not the whole gauge, nor would it have a cooldown. This would allow possession to be more flexible, allowing the Reaper to delay it if using it the moment its available isn't a good idea.
When you use possession, it changes your 1 2 3 combo into a new, more powerful version. Summon skills aren't available while possession is in use.
There can also be an oGCD attack on a 15-20s cooldown where the reaper poses holding their right arm as if they're in pain while pulsing out a shadowy AOE attack. It'll give you void link stacks, and when you get three, the skill will change to a new one, or perhaps will enable a new GCD skill. Some sort of scythe bum rush for a lot of conal damage, and give you an additional 20 points to the job gauge.
In addition, there can be a channeled ability similar to meditation, but the Reaper would pose as if their eye is giving them great pain. Every five seconds, they gain a stack of void link, up to three stacks.
For utility, every 90s or something, the reaper would be able to use a raid wide damage buff. Flat, crit, direct hit, whatever, but something comparable to battle litany, because I think every DPS should have at least that much. Unless if SE decides to put most of raid utility somewhere outside of melees.
Finally, normal generic healing and stun skills like all other melee DPS.