Let me preface this with the standard disclaimer of COR is still the least popular job in the game etc., so make any claims of "this will break the game wide open!" in moderation, please.
Thinking about the options for the upcoming Dancer's Roll and Scholar's Roll, there are a few possibilities that come to mind.
Scholar's Roll
+Conserve MP- This would work in essentially the same manner as Fighter's Roll; a simple increase to the proc rate of Conserve MP. I don't know how valuable the trait actually is, though; given that the average bonus to 2A rate from Fighter's is approximately +9%/+14% (without/with WAR), would a similar proc rate on Conserve MP be worth the paper it were printed on (relative to other available rolls)? I'm sure someone can break it down mathematically.
+Fast Cast- This would provide another useful mage buff for COR, while helping to fill in (on the casting side) for the lack of Haste rolls available. Again, since I'm no mage, I'm unsure how much would be "overpowered," but it seems that a rough average of Fast Cast+10/15 (without/with SCH) wouldn't be out of place.
Regen- Given the existing guideline from Squenix that an average roll is generally to be more powerful than one of the equivalent song, and XI is to be more powerful than a pair of said song, I think it'd be pretty fair to put base regen values at 4x that of Evoker's (sans SMN), with the job bonus being +2 to net values. That'd result in an average of 11.1HP/tick with SCH and 9.2HP/tick without.
Dancer's Roll
Regen- See above for details. It seems fairly likely that COR will get Regen from one of these rolls, but it could easily be either one.
Haste- To be honest, I'd rather have Regen, especially if Scholar's Roll is +Fast Cast. Fighter's is generally a good enough substitute for haste, and even if it's not, I'd rather see them buff Fighter's instead. But as far as the numbers go, something like the old ACC values for Hunter's (with RNG) should work: +12.75 average, +23 on XI. Add +3 with DNC in party and that should turn out fairly well.
Regain- Here is the elephant in the room. This roll would be useful for many reasons (not the least of which would be enabling DNC to do something in fights where it's impractical to melee for all their TP), but the immediate and overpowering sentiment is "broken beyond belief". However, given the existing average +Store TP of Samurai Roll (32.8 with SAM/23.6 without), I think duplicating Evoker's returns in TP/tick is reasonable. (For comparison's sake, each 1TP/tick results in an extra 20TP/min.)
XI Wiki

hoping upcoming rolls being good
