Assuming the 'skill glamour' idea Ive mentioned before was implemented, ie: get base spells from questing, learn 'reskins' from mobs to retain the 'learn' aspect of it's identity, have special effects as 'Showmanship' effects or whatever, so they only apply in unsync and Carnivale. With that in mind:

basic filler:
Direct ST hit (Watercannon style), Line AOE hit (Glower), Conal hit (Flamethrower), Circle (ram's voice), targetted circle (choco meteor), the circle ones can double up as AOE filler too. Reason for the different shapes explained later.

total of 5 buttons here

Special damage stuff:
3 Primal skills, a 30s, 40s and 60s for the main 6 primals. OGCD gapcloser (reskins are Jkick or Flying Frenzy, etc).
Selfbuff and DOT. Whistle and Bristle reworked to work on both damage types, and be same potency, are now true reskins.
60s GCD with guaranteed crit/dhit(can be reskinned to Triple Trident, Rose of Destruction, Matra Magic, all do same total potency cos of guaranteed CDH. eg TT does 3X200p, RoD does 600p, MM does 12X50p, all are 600p total.)
Maybe a 2min that does massive damage, (can reskin to Nightbloom or the Sophia one)
LVL5Death changed to be big hit of damage (like 700p minimum), instakill effect moved to be unsync only (allows for easier glam farming from old raids!). reskins include ultravibration, launcher, etc.

8 buttons here

Utility and raidbuffs:
Offguard as 60s CD, increases damage done to target by the BLU (like Trick), Peculiar light as 2min, debuffs all enemies hit to take 5% more damage (all types), like AOE mug.
Libra, a part of BLU's damage rotation, does a bit of damage and dictates a shape of GCD spell that will do bonus damage for a while. This is the reason to use eg the Cone over the Line, or the Circle over the Direct ST hit.
White Wind as a 5min CD, restores HP equal to the BLU's current HP. Long CD makes it less exploitable, but could potentially see interesting interplay with a WHM, Bene the BLU and then they WW for a HP to 1 mechanic. AST has macrocosmos, so this is fine.
Cold Fog as a 1min selfCD, reduce damage taken by 20% for one hit. (can reskin as Diamondback, Chelonian Gate)

5 buttons here

other stuff:
Mighty Guard as a raidwide mit, 10% damage mitigation for the team and a shield of say 200p (works a little bit different from RDM's Barrier)
Moon Flute as a 2min selfbuff for big burst, doesn't pacify at end of duration (can reskin to other things like DragonForce)
Final Sting reworked to cost all of your MP instead of HP
Blood Drain reworked to restore a lot more MP, maybe 2000. This allows Final Sting as the final hit in raidbuffs, then a Blood Drain to get back some MP to keep casting, would be an optimization thing.
Angel Whisper, CD reduced to 1min, instant cast
Loom reworked to have more range, and instantcast OGCD.

6 buttons here

Total of 24 buttons. Personally I'd have wanted BLU to be a tank (get hit, learn skill is a common BLU learn method in other games), but now it's categorised as a dps, this is what I'd hope for. I could list how I'd match up every skill for each reskin set but... there's like 80 skills, I cannot be bothered. Maybe tomorrow