So, what's your opinion on current healer jobs

[Recon1o6]

As much as anyone would like to admit, the buff extension for Ast was not as extensive as you'd think

Actually, yes, it was. Not so much in savage for those dps numbers everybody craves too much (though I strongly suspect were roll dps the thing back in hw and sb, it would shine better), but in alliance and dungeons it was amazing. Stacking your buffs on the mt followed by a CO and TD meant you go entire pulls with barely a heal if you really tried.

Ast had mp issues in previous expansions

Ast's were only slightly mp negative in diurnal and more so in nocturnal on account of it being objectively inferior in being unable to stack its shields unlike diurnal's regens which do. Slight mp negative is a good thing, as mp management is both fun when balanced right and integral part of healer balance.
Whm has practifcally infinite mp. It will run dry, but only if you aren't using your kit to even a basic level, which no player should be doing at 70 nevermind 80

Astro's ewer was excellent mana regen and boostable at that, at the cost of it being unreliable. But that's what made it fun, you had redraw to adjust your cards to as of when you needed htem, failing tha tin sb minor arcana could grant a free heal.
Luminerferous aether was the mp restorative in HW. It did the equivalent of 1/5 to 1/4 of your mp depending on a few factors

[Lilseph]

Stacking your buffs on the mt followed by a CO and TD meant you go entire pulls with barely a heal if you really tried.

It was nice to have and and satisfying to pull off (no amount of effort can overwrite bad luck), but again, where would you use it outside of that one specific instance? What if you never get the exact card combination for the entire dungeon? Are you going to just hold onto both abilities indefinitely till you get it? Genuinely curious.

Ast's were only slightly mp negative in diurnal and more so in nocturnal on account of it being objectively inferior in being unable to stack its shields unlike diurnal's regens which do.

Eh, it's about the same as it is right now. The reason why its so noticeable in ShB is that they removed both Ewer and the ability to extend Lucid while not giving any other external source of MP recovery to compensate. Adding on to buff extenders, there were posts like this regarding MP issues such as always pairing Opposition with Lucid.

[Recon1o6]

Longer aspected helios regen so you can spend more time on attacking spells, Extended balance on everyone in a group during a raid (6 seconds makes a difference), longer crit boost on a bard or monk, or arrow buff so that player could perform better for longer, extend the mp regen ewer on that poor rdm who you just revived from a lag spike induced death...

There's loads of ways it could be used and it required careful thinking to see who'd get the best benefit.

And if you actually read that post, you would have seen that it was likely the player not using their abilities correctly rather than actual mp negativity because SB astrologian required proper management of her tools to function well, which said player was not given they kept the expensive Aspected benefic up as much as possible (very high mp cost)

Lastly Astro has no mp recovery whatsoever now outside of lucid. That's down from having luminerferous and ewer in hw, and further down from just ewer of sb outside of the role action.