Do you then feel that in this case, where foes have two chances to fail what should be a pretty high save DC, that its too all or nothing for a 3rd level slot as a swift action?
As to slowing 12 henchmen being inefficient, if they are trivial threats then I agree and that's where I would wave them away with a pink mist spell, if they are not trivial then slowing them makes them trivial.
At 15th level my Int should be around 30 (25 base, +6 int headband, maybe a tome or two by then) the save on this spell would be DC27; assuming that the pathfinder charts (
http://paizo.com/pathfinderRPG/prd/monsters/monsterCreation.html) are indicative of what we will be facing then a CR 15 critter with a strong will save has a +18 will save or a 55% percent chance of making its save the first time, with the iterative second save (from persistant) if I did my math right leaves each enemy at 69.75% chance of failing one or both saves.
I'm not planning on playing a one trick pony, and I'm not looking for one spell to rule them all; but what I am looking for is a nice trick that can be pulled out to apply favorably in many situations. This trick uses 2 traits and 3 feats that will benefit no other spell, but leaves me with extend, persistant, and quicken, all of them solid metamagics, applicable to other spells. I also lose nothing from my daily casting since I can prepare any spells I want and convert any that are not useful currently into Slow.
To be honest I agree with your points but I'm not sure the "standard reply" has anything to offer the question asked, I still get to pull all the BC shenanigans, I still get to buff my party, I as a player have to be begged to prepare more than 1-2 direct damage spells, my most powerful spell at first level is wall of meat, I mean enlarge the Barb. I'm really just trying to see if I've blinded myself to shortcomings or restrictions that I hadn't looked into.
Thanks for the reply, I did carefully read it a few times (and will read it again) to make certain that I Grokked it.