Hi!
First, many thanks to Finkum and Pintofbrew for taking the time to look, think and answer me. I really appreciate it.
I realize the gems may be a bit nonstandard, but they were basically my attempt to get up to my hit cap in a smart AND efficient way, so that I could take advantage of my item bonuses where I could, which while not the most helpful for DPS are nonetheless useful (the extra stam really helps with Malacrass) and also maintain decent DPS. I decided to socket the hit/mp5 gem not particularly because of the MP5, but because I had the epic gem and it was a way to get +hit into a blue socket and still qualify for the item bonus, which I thought was smart. The mp5 is just icing. But I admit it's not the best itemization

.
It's really the same situation with the legs I chose -- if you just compare the two badge legs against one another, the others are vastly superior DPS. But if I chose the others, then I'd have to make up 25 spell hit elsewhere, and at the time my calculation was that doing that with the other +hit items I have would, net, result in less DPS.
I made a careful calculation about how I could maximize my spell hit while minimizing the amount of DPS I had to trade off to get there. (For instance, I could regem with all or even mostly +dmg gems and make up the spell hit with other items, but my calculations showed that if I did that, with the items I have currently to swap for, it would be a net DPS loss -- for instance, the +hit items I can swap for right now are: [Jewel of Infinite Possibilities] and [Ashyen's Gift].) It's possible I made some errors somewhere or another though, but at the time this all made sense -- I think I'm going to take Pint's advice above on the swaps though; my concern is retaining +hit in a way that would also allow me to retain my item bonuses. I'm not always married to this (note my pants), but I want to to the extent that that's possible, and smart.
Definitely some ZA pieces I can still pick up, it's just a matter of time. Sadly, my boots are indeed terrible! I have now about 130 badges and am having to miss our Kara badge runs lately because of scheduling issues so I'm being rather careful with how I spend them (holding out for the possibility of eventually buying those DPS pants, in case I get another piece that would let me make up +hit elsewhere). Since there are some nice boots that drop from ZA, and I've already seen them drop twice ( >:| ), I am hesitant to spend the badges on the [Boots of Incantations] just yet. But that's definitely an option. In the interim it might make sense to just fork out some cash for the Boots of Blasting as you mentioned.
Forgot the darn spellthread; I bought the pants the day the badge vendor came out and there was no Runic to be found, then just forgot. /blush
On the mana issue: Yep. No spriest. We HAD a shammy, but I think she's gone for good as of last week, which makes things even tougher. Prior to her leaving, our typical group was:
Feral druid tank and pally tank (sometimes prot warrior tank depending)
Holy priest and holy paladin (or sometimes resto druid and holy paladin)
Combat rogue and enhance shammy
Fire mage (me) and destro 'lock
And a few folks that swap out, between rogue/hunter/frost mage/boomkin to round out.
We have some fairly significant group synergy issues though. We're a small, cozy guild that likes to let people play if they want to play; that has in the past caused problems with our group makeup. It also means when someone doesn't show up for ZA it can cause problems. And, now we'll have to find someone to replace our shammy.
As a side note, I easily got up to about 920 DPS on Prince last night with my new spec (2/48/11), #1 on the meters I imagine because our meleers have to do so much running in that fight. And I did notice the extra mana burn. Still reserving judgment until I try it out in ZA.
No frost for me, as much as I appreciate what seems to be some strong pro- arguments at this level.

Just doesn't fit my playstyle, but I do appreciate the arguments.
Thank you again!