Only thing I can think of is the priest dot nerfs might hurt next patch if they stick but other than that it looks good to me. Sounds like your looking to the Spriest for utility anyway and not so much raw damage wo maybe the nerfs wont inpact you to much.

On a slightly reltated note I've been toying with the idea of a 5 disc priest pvp team and had the thought to make one shadow for the fear/disarm and silence that the disc priest all lack. The downside is it lacks the full effect or round robin pain supression, power word barrier and mass power infusion I'm looking forward to.