I'm not wearing the pieces yet, so can't speak to whether it's worth it, but as far as farming the mats, I just thought I'd chime in and say I really didn't find it that hard, and it didn't take that long, so even though you aren't a fan it may not be as painful as you think. I used my druid to get the mats for Spellfire and they're all ready in the bank for when my little level 47 mage finally makes it up.
I farmed all the primal mana myself in the Crumbling Waste in Netherstorm. NEVER anyone over there. Phase Hunters and Nether Rays. You can skin them too for a little extra leather cash.
Even though fire immunity wasn't a problem for the character I was farming with, I used the advice I got here to farm other primals and buy fire. There's just always so much competition for fire elementals and it slows you down. On my (low-medium pop) server there'll be 4 people camped out in their section of the Elemental Plateau, while 20 feet behind them there's nobody near the water.
If you have fishing, farming water motes is VERY quick. I take a short side trip over to the Elemental Plateau each time I log in, fish the pools of pure water, kill the elementals around them, fly off with 2+ primals and get on with whatever else I'm doing. Just that little 15 minutes (if you include travel time) doesn't much interfere with whatever else you're doing and it adds up.
At level 61, you can probably start handling the bog lords in the Dead Mire in Zangarmarsh for motes of life. You'll get twice as many off them if you also have herbalism. Especially if there's also somebody killing them nearby who doesn't have herbalism and you can pick their corpses as well. :) They also drop unidentified plant parts, which if you aren't grinding Cenarion rep auction pretty well.
Water and life are both cheaper than fire, but I found I could farm them at least twice as fast.
Edited, Mar 7th 2008 9:37am by teacake