Even looking at personal numbers on fflogs for the current savage raids AST is outDPSing WHM. I'll take a quick look at 99th (best), 75th (good), 50th (average), and 25th (below average) percentile numbers:
O9S-
99th: AST is 3758, WHM is 3370
75th: AST is 2659, WHM is 2520
50th: AST is 2200, WHM is 2160
25th: AST is 1760, WHM is 1752
O10S-
99th: AST is 3162, WHM is 3019
75th: AST is 2373, WHM is 2328
50th: AST is 2058, WHM is 2055
25th: AST is 1740, WHM is 1781
O11S
99th: AST is 3478 (and actually beating SCH, too), WHM is 3102
75th: AST is 2626 (and actually beating SCH, too), WHM is 2454
50th: AST is 2301, WHM is 2212
25th: AST is 2005, WHM is 1973
O12S (p1)
99th: AST is 3323, WHM is 3208
75th: AST is 2552, WHM is 2568
50th: AST is 2247, WHM is 2301
25th: AST is 1949, WHM is 2080
O12S (p2)
99th: AST is 3545, WHM is 3330
75th: AST is 2589, WHM is 2595
50th: AST is 2256, WHM is 2342
25th: AST is 1966, WHM is 2057
So at best, WHM is pulling equal with AST in personal numbers at average play, and falling 10% behind in some cases at high level play. The only stand-out seems to be O12, but I don't know if that's just because there are only about 360 WHM parses registered compared to almost 900 ASTs. So if we're just looking at personal contribution it's not too bad, overall.
But what does WHM bring that AST doesn't? Spammable Cure III? Is that it? As has been said before, if your niche is 'the big green number guy' you can't use your niche properly, because it means big red numbers have to come your way. And if big red numbers come your way that only big green number guy can deal with, then the other two are completely obsolete because they physically can't keep up, just to give you your niche. If they want every job to be viable in every instance they can't have that.
Also here are the numbers for Suzie while we're at it in case you want slightly less than Savage.
Suzie-Ex
99th: AST is 2851, WHM is 2959
75th: AST is 1848, WHM is 2008
50th: AST is 1451, WHM is 1628
25th: AST is 1108, WHM is 1267
These numbers are actually somewhat better, with AST falling consistently around 10% behind WHM from 75th and below (99th is only about 4%). That said, I'm not too familiar with the DPS that an AST's cards alone deal in raid buffs over the course of a fight, so I'm unsure if 10% of a WHM's output would match it. Could someone possibly throw that my way?
And since I'm on a roll here, I'll do the dungeons and round the set. By the looks of it FFlogs bases dungeons on clear time in seconds or something (so lower is better):
The Burn-
99th: AST is 710, WHM is 693
75th: AST is 933, WHM is 888
50th: AST is 1036, WHM is 998
25th: AST is 1183, WHM is 1141
Arboretum-
99th: AST is 746, WHM is 736
75th: AST is 923, WHM is 899
50th: AST is 1025, WHM is 994
25th: AST is 1164, WHM is 1123
So yeah, if you want to shave 20-40 seconds off your dungeon run, I guess you take White Mage? Wow!
tl;dr It seems the only thing that's somewhat balanced right now is potentially Suzaku between WHM/AST in terms of DPS and contribution. And dungeons, I guess, but they hardly really need balance if we're being honest. Scholar almost universally dunks them both, which is a different discussion altogether, however.
I'd look into healing output, in those fights too, but that's not the current topic. I might make another post comparing healing later.