Shifter is a weak LA +0, and not particularly interesting. Net -2 abilities and no standouts to recommend it over the top shelf picks, so eh.

Shimmerling Swarm: oh look, a swarm...with -4 Int, -8 Str, and 11 Fey RHD, meaning losing 6 points of BAB across eleven RHD. Honestly, the only thing to recommend this over other swarms is the 50 ft perfect fly speed; I don't see any good way to construct an adequate initiator or Incarnum build, you are not going to be a skill monkey, and good luck with generic martial. You get +4 Wis and +8 Cha, but you can easily get that with a better chassis and less RHD if you want a caster. In return, you get a 60 ft Dazzle effect and a 300 ft fascination effect, both not friendly to allies...yaaay.

Blech. LA -0, easily.