Right now the script we are using is a really hard healing fight, so it will favor mastery because of that. If you adjust the slider enough towards DPS, it will start to dump mastery for other stats, but you have to go more than half way towards DPS.
Mastery, point for point, is just an insanely good stat for resto shaman. I look at it like this: When there isn’t a ton of healing to do, your healing is kinda “meh”. When there is a ton of damage and you really need healing, it is amazing. So yeah, in the situation where everyone stays high health and you just want to top people off… you’ll have to cast a few more spells. But you will be able to save people when it matters. I have a hard time seeing a downside to this strategy for gearing a resto shaman for healing.
Once damage comes into play, then you will want to shed a lot of mastery.