I think Concurrence is over-powered. "On the coming day, she may use the selected spell as a spell-like ability once per day per point of her Wisdom modifier (minimum 1)."
So, if she has a Wisdom of 18 she gets to use the spell as a spell-like ability four times day? And she can use spells that are 1+1/4 of her level.
"At 1st level, a sagittarius may only receive a single concurrence each night. At 5th level, 9th level, 13th level, and again at 17th level, a sagittarius gains the ability to receive an additional concurrence. Each additional concurrence grants her a full complement of uses of a different spell-like ability, and a luck bonus on a different skill (as well as the potential to burn the luck bonus for the greater one-time bonus)."
So a 5th level she gets two spell-like abilities that she can use 4 times a day; at 9th she gains a third and so on. So this means she effectively gets two 6th level spells at 5th level; three 9th level spells--there aren't any 11th level spells--at 9th level and so forth. Even spellcasters don't get 9th level spells until 18th level. This is way too unbalancing.
I think you should limit her to 0-level spells at 1st level, 1st level spells at 5th level, 2nd level spells at 9th level, 3rd level spells at 13th level and 4th level spells at 17th level. Otherwise she's just too powerful.
And to really put it over the edge every day she gets to use a skill she doesn't have with a luck bonus? That is just too much if you ask me.
BTW, what spell list is she limited to or isn't there one? If she can just use any spell as a spell-like ability then wish comes into play at 9th level and that is terribly unfair.