I understand this probably would've been more useful to say before U9 was planned out, but I started thinking about this with all the SLA related content and changes going around on Lamannia.
The purpose of Spell-like abilities that replicate spells, such as the Archmage and Savant SLAs, as far as I know, are to give the class access to an ability they can use at low SP cost compared to actually casting it:
So my question is, wouldn't SLAs better fit their actual purpose by reducing the power of SLAs, then making them completely free ala FvS SLAs? As is, it's no secret that someone spamming their SLAs as fast as they can in no way compares to the power of just having a melee in party.
Basically, here's the changes I'd like to see to Savant and Archmage Prestiges in regards to SLAs:
Archmage 1: Lose the Spell-Like Ability
Archmage 2: Lose the Spell-Like Ability and Arcane Bolt
Archmage 3: Access to 1st Spell-Like ability of your primary Focus; SLA is completely free SP wise, normal cooldown as the appropriate spell.
Archmage 4:Lose Arcane Blast
Archmage 5: Access to 2nd Spell-Like ability of your primary focus, and the 1 spell-like ability of your 2nd focus.
Really, you could just condense Archmage to the 3 normal tiers, and move Spell Mastery 2 to the final tier instead of the 4th tier. Reason for the loss of Arcane Bolt and Arcane Blast is that they really didn't fit in with the prestige unless you were an Evoker; and tbh, I honestly believe that free SLAs with normal cooldowns would be a large improvement for the prestige, well worth losing the Arcane abilities.
Savants: Remove SLAs for level 2 and 3 spells, move the level 1 SLA to tier 2 Savant and make it completely free SP wise with normal sorcerer cooldown.
Of course Metamagics would still apply to all these SLAs.
Understandably, this is somewhat the purpose of Echoes of Power; problem is, Echoes of Power gives SLAs a concrete use once you run out of SP; until you run out of SP, you're quite often going to be better off using your most powerful spells, unless you're going through a module where resource conservation is extremely important.
Finally, this would give a reason to play Archmages; the free tier 2 SLA, while not game changing, is an actual real advantage; as is many people don't take the SLAs over the minimum tier they want for certain spells, because the loss of SP isn't worth it.
Oh, and if anyone thinks that unlimited spell use is anti-DDO, that idea went out when Radiant Servants could regenerate Divine Vitalities; now Spell-singers can regenerate SP-regeneration songs and mana already has the potential to be unlimited.
Also: If this was added, I would have to advocate the removal of Echoes of Power (Or for it to never be implemented?). If this was implemented, the more logical way to give low level casters something to do despite low SP bars is give them free level 0 spells that metamagics can't be applied to (I'm thinking Acid Blast/Spark of Fire/Spark/Frost each for 1d3 damage or something of the sort)