Yeah, the Aasimar0 is +2 cha, medium outsider, 30', Darkvision 60', +2 listen/spot, Resistance 2/ Acid/cold/Elec, light(sp), pally.
As is, though, you're knocking down the half celestial LA by 1. The question is whether you think the outsider type and darkvision is worth 2 points of wisdom and improving light to daylight
The Faerun Aasimar also has 30' move, darkvision 60', +2 spot/listen, and resistance 5 acid/cold/electricity, and daylight 1/day.
From the book.
Planetouched: Planetouched are humanoids (not outsiders) with the planetouched subtype. They are susceptible to spells and effects that specifically target both humanoids or outsiders. Charm person works against them, and so does banishment. This trait replaces the outsider entry in each planetouched description.
As he is right now, Charm Person, and anything that affects regular humanoids, now works on him, as well as anything that works on outsiders. He's a double-edged sword.
So the question really is, is do I think one level of celestial is worth Str +2, Con +2, natural armor +1, disease immunity, poison resistance, spell-like abilities, and spell resistance (lesser). I suppose it is.