Ok... I have made a little testing with a mage. The new spells should be interesting and open new ways of killing stuff with a mage...
However, a large part of those spells is still of little or no use at all... so here is the result of my testing (done with a mage at 18/120 and 18/*** int):
Magic for beginners
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- magic missile (level 1, fail 0-2%, dam 3d4-12d4): rating 5
low cost, low damage... nice at very low level, totally useless after level 20 or so
- detect monsters (level 1, fail 0-2%): rating 7
very useful for the first half of the game, less useful once the character has full ESP (still helps detecting annoying mindless critters like drolems)
- phase door (level 1, fail 0-2%): rating 6
very useful in the early game, almost useless later on
- light area (level 1, fail 0-2%): rating 9
since mages don't have the Clairvoyance spell, this will be used for the entire game to lighten up the dungeon
- cure light wounds (level 3, fail 0-2%): rating 3
not very useful... except at very low level when your character has low hps and full mana (halves the time spent resting)
- find hidden traps/doors (level 3, fail 0-2%): rating 10
one of the best support spells in the game...
- stinking cloud (level 3, fail 0-2%, dam 11-35): rating 1
low damage, no poison effect, resistable by too many monsters... totally useless
Conjuring and tricks
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- confuse monster (level 5, fail 0-3%): rating 2
only useful against a single monster... and a monster that doesn't resist confusion
- lightning bolt (level 5, fail 0-3%, dam 3d6-10d6): rating 9
this is an awesome spell up till midgame... the beam effect (even if the damage is really low) helps clearing pits and packs of monsters in no time
- trap/door destruction (level 5, fail 0-3%): rating 10
too nice when clearing vaults
- cure poison (level 5, fail 0-8%): rating 1
I can't find any use for this...
- sleep monster (level 7, fail 0-3%): rating 1
this spell doesn't seem to work (everything seems to be unaffected... probably a bug)
- teleport self (level 7, fail 0-8%): rating 10
always helpful to get out of trouble quickly...
- spear of light (level 7, fail 0-3%): rating 5
useful to lighten up corridors at low level and hurt orcs... useless later on
- frost bolt (level 7, fail 0-13%, dam 5d8-16d8): rating 4
high fail rate at low level, high mana cost... and quickly obsolete
- wonder (level 7, fail 0-23%): rating 2
I don't see the point of this spell... you need to cast it many times to get something useful and the cost is totally prohibitive at low level
Incantations and illusions
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- satisfy hunger (level 9, fail 0-18%): rating 10
since a character always needs to be fed...
- lesser recharging (level 9, fail 18-48%): rating 9
since wands and staves can't be destroyed anymore, the spell has become incredibly useful... especially to recharge staves of enlightenment (mages don't have any magic map spell)
- turn stone to mud (level 9, fail 0-17%): rating 10
how would you do antisummon corridors without this spell?
- fire bolt (level 10, fail 0-23%, dam 7d8-17d8): rating 4
same as frost bolt... fail rate is too high at level 10, and the spell becomes obsolete at level 15
- polymorph other (level 11, fail 0-18%): rating 1
another spell that doesn't seem to work
- identify (level 11, fail 0-3%): rating 10
now this spell has a very low fail rate for mages... very handy
- detect invisible (level 15, fail 0-13%): rating 6
this spell won't be cast often... but it's very useful to detect those damn Qs
- acid bolt (level 15, fail 0-23%, dam 10d8-19d8): rating 6
basic offensive bolt spell until level 35... not very effective though
- slow monster (level 17, fail 0-23%): rating 3
a marginal spell... many critters resist, and the effect isn't long enough
Sorcery and evocations
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- frost ball (level 19, fail 0-28%, dam 49-80): rating 2
high fail rate, high mana cost, ridiculous damage
- teleport other (level 23, fail 3-33%): rating 10
if you can't kill it... just teleport it away
- haste self (level 25, fail 8-38%): rating 10
always nice to have some speed boost... fail rate is a little high and duration is quite low though
- mass sleep (level 25, fail 0-23%): rating 1
this spell has currently no effect (bug)
- fire ball (level 26, fail 8-38%, dam 81-105): rating 2
same as frost ball... too costly, insufficient damage, high fail rate
- detect enchantment (level 30, fail 13-43%): rating 8
interesting spell... helps finding those artifacts on special levels
Resistance of scarabtarices
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- resist cold (level 10, fail 0-23%): rating 2
nothing really breathes cold powerfully at low level... and there are potions for that
- resist fire (level 10, fail 0-23%): rating 2
same as resist cold...
- resist poison (level 25, fail 0-18%): rating 2
only useful for 3 levels... if you really need to resist poison
- resistance (level 28, fail 8-38%): rating 10
another vital support spell... double resist lows is always great at high level
- shield (level 32, fail 18-48%): rating 8
gives +50 AC... not to be neglected when fighting monsters that do massive melee damage
Raal's tome of destruction
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- shock wave (level 16, fail 0-13%, dam 26-60): rating 10
this will quickly become the mage's favorite spell... this stuns almost every monster for quite a while, allowing mages to finish them quickly with a nicely enchanted bow
- explosion (level 20, fail 0-23%, dam 60-120): rating 3
this would have been nice (almost no monster resists shards)... but unfortunately it's too costly to be of any use, and there is currently no shard effect from this spell
- cloudkill (level 20, fail 0-23%, dam 50-65): rating 4
another quite useless spell because of low damage, but because of low cost, it can be used to get rid of packs of low level monsters quickly (canines, hounds...)
- acid ball (level 20, fail 13-43%, dam 60-90): rating 3
same as frost/fire ball... and even with a higher fail rate
- ice storm (level 27, fail 18-48%, dam 104-150): rating 7
I'd say this will be the main ball spell for mid level mages (first spell dealing over 100 damage)... stunning effect, radius 3... nice, but you need max INT to be able to cast it effectively, and it will eventually become obsolete
- meteor swarm (level 30, fail 28-58%, dam 3*45-4*55): rating 3
simply useless because of the fail rate...
- rift (level 35, fail 3-33%, dam 40+35d7-40+50d7): rating 10
once you know how to cast this spell effectively, you will kill almost everything with it
Mordekainen's escapes
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- door creation (level 13, fail 0-13%): rating 10
your favorite antisummon spell
- stair creation (level 24, fail 0-23%): rating 10
sometimes you want to powerdive your character... this spell is for you
- teleport level (level 28, fail 8-38%): rating 5
probably more useful for ironman servers (though it doesn't allow to go up anymore)
- word of recall (level 30, fail 18-48%): rating 10
pure support spell
- rune of protection (level 36, fail 13-43%): rating 10
major improvement for mages... this will maybe counter the loss of GoI
Tenser's transformations
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- greater recharging (level 30, fail 38-68%): rating 10
more charges for your staves of enlightenment
- elemental brand (level 32, fail 38-68%): rating 10 (for now)
this spell is totally useless... but for now it allows to create piles of 99 bolts of flame that can be sold for 10k each stack
Kelek's grimoire of power
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- earthquake (level 20, fail 3-33%): rating 2
I don't see a real use for this
- bedlam (level 25, fail 3-33%): rating 2
... and for this
- rend soul (level 25, fail 23-53%, dam 11d25-11d50): rating 10
massive damage at quite low level... but of course you need the book
- banishment (level 30, fail 38-68%): rating 10
if you don't like hounds...
- word of destruction (level 33, fail 23-53%): rating 10
the panic key...
- mass banishment (level 35, fail 33-63%): rating 10
... and the vaults are easier to clear now
- chaos strike (level 38, fail 33-63%, dam 13d38-13d50): rating 3
would have been nice... but polymorphing everything isn't really funny at high level
- mana storm (level 42, fail 38-68%, minfail 14%, dam 384-400): rating 5
the most damaging spell for a mage... still too high fail rate, even at level 50 with max INT!!!