Wel damn, that sucks. LA really does give you a kicking but i suppose that the Pixie does give you a lot and is still worth it.
Honestly, I find only LAs of +1 or +2 to be worth it. The only LA +3 I'd consider playing is the Half-Dragon. The loss in saves, base attack, skills, and hit points is generally not worth it. The Pixie does give you a lot of interesting stuff, but here's what you're missing with the Rogue:
+3 Base Attack Bonus
4d6 + 4 * Con Mod Hit points (average of 14 hit points missing with no Con Mod)
32 + 4 * Int Mod skill points
+1 Fort, +2 Refl, and +1 Will
2 dice of sneak attack damage
But anyways, I'm derailing. I'll stop.