Wrath of The Lich King Gear Needs

A bit late to the discussion, but regarding spells costing X% of our base mana, what's the purpose of having a huge mana pool if you are a healer or dps? Are paladins the only ones getting spells that cost X%? Or will the same go for mages, locks, and healers?
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Thing is if you're using daggers in both hands and Sinister Strike isn't recommended then how would you build combo points?

It seems strength is our new threat stat. The new spell damage items don't seem to have any Stamina. Look at the difference between these two items:

Melee Shield
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_048.jpg

Caster Shield
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_014.jpg

Or these items:

Tanking Plate
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_039.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_040.jpg

Melee Plate
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_010.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_060.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/ingameshots/loot/plate_chiseledstalagmitepauldrons.jpg

Caster Plate
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_057.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_038.jpg

The caster plate is almost all missing stamina, while the Tanking plate has no Intellect or Spell Power. These are all Bind-On-Equip items.

It seems the caster items with Stamina/Intellect/Spell Power are all Dungeon Drops:
http://static.mmo-champion.com/mmoc/images/wotlk/items/rare/rareitem_004.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/ingameshots/loot/plate_chestplateofthenorthernlights.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/ingameshots/loot/plate_greavesoftheblueflight.jpg
http://static.mmo-champion.com/mmoc/images/wotlk/ingameshots/loot/plate_insulatingbindings.jpg

Again, no avoidance stats on any of these pieces. So what should we be wearing?

To clarify, X% of base mana means your mana pool when naked, unbuffed and (I believe) untalented. So buffing your int doesn't increase the cost of those spells, and they cost a smaller % of your *buffed* mana pool than is listed.
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Also posted in general:

Some info on spells and scaling from Elitist Jerks:

so, what im guessing ( god im nervous ) is that stacking stam gives us spell dmg and str gives us BV, so... JCer pallys are going to have all the badass bop gems to stack str and stam? if they scale the sameish in wrath... does that sound a touch op to anyone else? i think im going to start lvling JCing.