Okay, this is coming strictly from my experience as an Enhancement (Melee) Shaman. Prior to 3.3 my dps wouldnt seem to budge.
The solution i found had to do with my aoe options. Before they change the "fire nova totem" to a fire nova "spell""- where ANY fire totem will give off the former "fire nova effect" So now we can have a magma totem (continuous fire dot aoe) with the fire nova spell (huge aoe dps here). It is definitely worth working into your rotation (fire nova) and using the following talents and glyphs to help maximize dps.
(note, i omitted any information non-relevant to enhancement)
Elemental Tree:
Improved Fire Nova
- Increases the damage of fire nova by (20%) and cooldown by 4sec.
A must, this is HUGE dps increase, and the cool down is a great reason to find a spot for it in your dps rotation.
Call of Flame (3) talents)
- Increases damage of fire totem AND fire nova 15%
15% increase dps is a lot of increase and well worth the 3 talent points.
Elemental Fury (5 talents)
- Increases critical strike damage of fire totems by 100%
Glyphs:
Glyph of Fire Nova
Reduces the cool down of fire nova by 3 sec.
The thing to note here is that this 3 secs stacks with the 4 secs (2 per point) of reduced cool down, that's 7whole secs, which means we can have that many more "fire novas" hitting our mobs/target.
Blizzard took the time to add so many different ways to use this new spell well. I personally helieve it best suits enhancement shamans the best becasue we can just drop a fire totem (i use magma) by our mobs/target and we have an addiotal spell (fire nova) to use in our rotation- as opposed to an elemental shaman who would have to run and place the totem by their target, we have the luxury of always being all up in the targets face/back.
So thes are my reasons why fire nova is a MUST for enhancement shamans dps.