No, it doesn't. You missed the 20% proc chance there, too. You will be lucky to see one CD reduction per minute with that factored in. It also says reduce Asylum OR Assize's cooldown. I'm honestly not sure how that ends up working. Does it hit both if they're both on cooldown? Is it a 20% chance for one, then a 20% chance for the other? Is it a single 20% chance that then gets applied to one randomly? I don't have that information yet.
I have not seen many people saying Thin Air is weak. It's quite a powerful MP longevity button. Even if only used to spam Stone IV, it is no slouch whatsoever. It's obviously incredibly potent if used in conjunction with things like Holy spam. In fact, that's why tons of people whose posts you've probably skimmed over have talked about how much of a powerhouse white mage will be in dungeons with how much holy spam it will be able to get away with. I'm not concerned for MP at all with thin air, to be honest. It's STRONG. In raid fights with significant AoE, it's 100% worth considering how much AoE damage the white mage will be able to bring.
Also, Assize is now 60 seconds, not 90. With 3 lilies it's a 12 second reduction. Before you talk about how that's even more MP since it's on a shorter CD, I should remind you that if you are saving your lilies for Assize it means you are not using your other CDs in the process, particularly asylum which is not an emergency button so is not often saved for such situations. You are welcome to try to build 3 lilies for Assize every time; at the current numbers, on average, you should spam cure for almost the entire time Assize is off cooldown to obtain 3 lilies to reduce its CD again.
Practically, if you're trying to build lilies specifically for Assize, you're probably not healing efficiently since you're spamming cure/cure 2 instead of using Regen or Medica 2 to handle the types of damage they were literally designed for, and are very efficient for. That extra MP you're getting from casting Assize earlier is likely a wash, as you'd be in a better boat to begin with using efficient spells, including all the other ones that cost 0 but will consume your lilies. You would literally have more MP using other spells and idling in the downtime than you would by spamming cures instead.
Oh, and you're not spamming stone for our good single target DPS if you're doing this CD reduction fetch-quest, by the way.
You also call WHM heals 'potent as frick' when AST potencies are straight up comparable in every way, if not higher (Aside from having Cure 3 on demand - which you mention spamming of as for "bads," I might add). I also feel you overstate its single target DPS. I agree it's quite powerful when examined straight up with SCH's and AST's single target, but the total package is not as far forward due to the existence of balance and scholar's new fancy libra-crit toy. With PoM it's a lot of burst if a fight demands it (Hand of Pain).
Perhaps you're the one who needs to examine the info better, as you claim we should. There are factually two things incorrect with your post with the numbers we currently have, the 20% proc chance for the 5s cooldown reduction on crits, and Assize being 60 seconds now.