If playing cooperatively (making skillchains, etc.), THF will ***over every other job's damage. If not playing cooperatively and just spamming Fudo, SAM can still pull even with THF by interrupting every skillchain with their stupid Light/Distortion WS properties.
Translation:
If other jobs use weak WS's and hold TP, then a THF using all their timers precisely and their strongest WS can do better. If the other jobs actually focus on doing damage and using their best WS and SCing with each other, then they will do more then the THF.
RS has sh!tty SC properties, Distortion + Darkness. To give an idea this is what other jobs would have to use to "work with you" and "make skillchains"
WAR: Not possible there isn't any WS's amongst GAXE, GSWD or AXE that are compatible with RS. Possibly Polearm cause SD has gravitation property or Requiescat from swords...
DRK: Quietus has Darkness, Entropy has Gravitation, no GS WS is compatible.
SAM: Tachi: Rana or Stardiver as all the rest are Light / Distortion / Fusion.
DRG: Stardiver is compatible with Gravitation, the rest are Light orientated.
BST: Onslaught and Cloudspliter are darkness, Primal Rend has gravitation.
BLU: Requiescat has Gravitation, otherwise the rest are Light / distortionn orientated. Can form self darkness every 2min using most powerful WS that can be used as springboard for RS.
NIN: Blade Hi is both gravitation and darkness, Blade: Ku is gravitation.
DNC: Can use RS, PK isn't compatible.
MNK: Asuran fists for gravitation
PUP: Stringing Pummel is gravitation
RNG/COR: WF, LS and Coronach are all Gravitation with WF and Coronarch having Darkness property.
Our of all those your limited to NIN, PUP, BST, DRG, Marks RNG / COR and other THF's possibly DNC though not sure how much they lose from not spamming PK @1000TP.
Any heavy DD would have to severely gimp themselves in order to "play nice" with RS. If they play to their best ability, using their JA's and firing off WS's every 7~9 seconds (and naturally forming lights with each other) then your position falls apart. If RS was Gravitation / Darkness then it would be useful for forming darkness with other powerful DDs. Right now there is a severe lack of powerful Darkness / Gravitation WS's which leaves Light as the big skillchain. Blame SE for their short sightedness.
The top DD's are all orientated around L3 Light SC's with many powerful WS's have secondary properties of Distortion or Fragmentation. And considering that SAM is WSing every 4~5 seconds while making their own Fudo spam lights (second DD screws up with the multi-step), the THF is the one interrupting it with their Distortion / Darkness properties.