The value of Carve and Spit.

[Syzygian]

C&S is the reward you get for managing your MP right.

If you have to use it for MP in a single-target scenario you failed.

In this sense it is the perfect lvl 60 skill.

"Did you learn how to play the job correctly these past 60 levels? You did? Cool, have a pseudo Fell Cleave off the GCD." - DA C&S

"Did you learn how to play the job correctly these past 60 levels? You didn't? Alright... here's a little bit of MP... git gud tho, will ya?" - non-DA (sadface) C&S

I fail to see how or why lvl 60 abilities need to be so grandiose. WAR gets Decimate, PLD gets Royal Authority... how are these innately better or more "suitable" lvl 60 abilities?

There's zero wrong with the skill. This whole competition thing you have described here between other oGCDs just doesn't exist. Your oGCDs are all on the same team - the team of your personal DPS - They don't compete with one another.

In the most basic of DRK rotations you maintain enough MP to DA every C&S and use DP on cooldown until you TP floor, without ever mana flooring.

Its use for MP is largely for when you are AoEing. That is literally the only time a good DRK should be using an unbuffed C&S. You should be managing your MP such that this is the case and this whole "DA C&S costs the MP of the DA and the MP you missed out on from not using it unbuffed" is bogus logic. Its safety net MP, not MP that is part of your routine resource management.