Celestial Apotheosis (casting 5). wholly within 18" choose a unit and it heals 1 wound, enemy units within 3" have -1 bravery
Claws of glory: casting 6: reroll hit rolls of 1 unit wholly within 18"
Walk between realms (casting 6): friendly unit wholly within 18", gains fly
Meteoric Convocation (casting 7): Pick an enemy within 24" and roll 8 dice, for each 5+ a MW
Mystical Unforging (casting 8): Pick an enemy hero within 12", D3 mortal wounds and on a 5+ his weapon gets yeeted outta the game.
Stellar Tempest (casting 8): pick enemy unit within 24" and roll a dice for each model, on a 5+ a MW
Celestial Apotheosis: does it ressurect? Also why only 1 wound? That'l barely get you anywhere in terms of healing. The combo heal + debuff is potentially interesting; but with how common battleshock protection is giving -1 bravery seems underwhelming at best.
Claws of glory: Seems eh rather weak, affecting only 1 unit. Also re-rolling hit rolls of 1 is like the one buff we actually already have easy acces to, so what exactly is the point? (a slann constelation, astrolith bearers, Stegadon skink alpha, sunblood, shadowstrike, thunderquake, terradons and rippers swooping dive, we have loads of variations of re-rolling hit rolls)
Walk between realms: a worse version of a slann's command ability? yay?
Meteoric convocation: seems a tad unreliable, but decent enough. The potential of 8 wounds is quite decent, but the average pay-off isn't too great.
Mystical unforging: Bit short ranged, especially considering none of our wizards want to be anywhere near an enemy hero with decent attacks. Could be interesting though depending on what exactly happens to the weapon.
Stellar Tempest: Decent anti-horde spell. Not much to say.
It's nice, and a much needed improvement. But as
@Erta Wanderer said, only the last two seem really decent the rest seems underwhelming.
There's 1 great use I can see for this though. If we get the ability to pick a spell on freshly summoned wizards it could make the summoning of skink starpriest a very solid and interesting strategic choice simply due to the sheer versatility it'd give, even with the more useless spells. Just imagine summoning a starpriest to suddenly allow your carnosaur to fly over an enemy screen to jump on some tasty squishy hero.
On a related note, does this mean we're also finally going to get prayers?
Just better scaling really, so we don't have a hard limit on how many summoning points we can make. Something like a Slann that is not the general can swap out his spells, but might only get 2 points for each spell, or have the astrolith bearer not give 1D3 if you have any atrolith bearer on the field, but give 1 point for each astrolith on the field.
Just allow skinks to help with it. It's by far the simplest solution & keeps with the fluff. Also, if done right it'd make skink heroes do something besides casting 1 spell each turn makes em feel a bit more impactfull.