One of my players (the sorceror) wants to take the elemental savant prestige class. He wants to specialise in Water.
How much would not having level 8 and 9 spells affect finishing the campaign?
Would having an elder elemental with 228 hp and dr 10 offset the loss of the spells.
Not having 8th and 9th level spells would be absolutely crippling. A 15th-level caster cannot even breach SR more than occasionally in most endgame cases, and will not be able to have a strong effect even with a lucky roll.
That said, elemental savant only loses two levels of advancement, and will therefore only be one spell level behind. That's not so bad. On the other hand, they don't normally get a pet elder elemental, either. Are you using an old version, perhaps the 3.0 version of the class?
I think he means Bonded Summoner from MiniHB - Elemental companion, but only 5/10 casting... I'd avoid it like the plague myself.
Definitely sounds like a bad idea. Given the expected opposition ( strong individual mobs as opposed to groups of small and weaker ones ) in the later parts, the elemental is only so much toast (e.g. an ablative shield ) , and lacking the "massive punch" spells like "Reverse Gravity", "Sphere of Destruction" or will weaken the character himself for little gain.
Plus, water elementals being pretty slow on land will tie the group down.
That said, there will of course be some utility value from the elemental and never let powermongering stand in the way of roleplaying.
But if said sorcerer is the main and/or sole arcane caster of the group, this may turn frustrating for the entire group.
Whether he takes Bonded Summoner or Elemental Savant, both are bad choices with regard to long term planning from an efficency PoV.
For a debate about the flaws of the Elemental Savant, check the threads of this forum, there was a debate about it some weeks ago.
And the Bonded Summoner, while maybe fun in a MMORPG way and reminscient of WoW, packs far too little punch. The immunities and defences gained, while nice are nothing to write home about and nothing you cannot gain from some cheap items. Yes, the elemental is handy, but the fact that one takes damage equal to its HD when it gets vanquished is a major drawback. It can be banished too, and once it dies, he will be without its help for at least 24 hours.
Consider how it will fare against a CR 11 demon or some other high CR critter (something that the STAP has lots of ), CR 18+ encounters being no rarity, and how he might permanently enhance it to improve its chances.... You can have gear made for an animal companion, but not so for an elemental.
So, definitely not worth loosing eighth and ninth level spells.But as nevermind said, never let power-gaming get in the way of good roleplaying.
Parting thought - a druid with the Elemental Companion variant (CM) might be a wiser choice if he insist on having an elemental sidekick. But that would mean a complete retooling or a new character