Strength buffs help the Tank and Big time on a Rogue for a higher Backstab. So Str, Dex to help with proc's, and that is all l would do low level. Higher level Haste for the DPS'ers.
Low level DoTs on a shaman are pretty weak. But you need to cast them often along with your DD to keep raising your skills. You Have to keep them raised to not have too many fizzles. Not a good thing to happen as a healer class when it is REALLY needed in a group or solo.
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Yeah Shammy Dots are debuffers like has been stated, but that is a good thing. Just like you get Malo spells higher up like a Enchanter gets. They really help.
A Shammy can be a very busy class to play both Grouped, worse and even Solo. Most spells never seem to last long enough.
[You must be logged in to view images. Log in or Register.] But it is one of the top classes on here and will be even better in Velious.