Originally Posted by
Bigslick
Well, IMHO it's time to offer some feedback. Int is only needed to point that you no longer have normal concerns about mana in an encounter after factoring in use of HoH, shadowfiend, and pot. After that stacking it is a very poor choice. If you feel that strongly about the value of crit, you get more crit budgeted from a crit gem than an int gem even after talents and kings, so you'd want to go that way.
As to 'more than enough SP for a raid environment,' there's not a magic number after which throughput is useless for a disc priest. SP = guaranteed throughput, and is not heavily regulated by RNG as is crit. You're running at 2575 SP unbuffed, which is extremely low for ICC content. At LK, it will not fully absorb the damage from infest (though it may absorb enough to keep people from dropping below the critical 90% threshold, not sure). At your level of progression you should really be aiming for a minimum of about 3k SP.
By regemming your Int gems to SP, you'll still have a healthy amount of crit and be sitting at 2995 SP, a reasonable amount. Swapping your Talisman of Resurgence to a throughput trinket will put you into much more comfortable position. Right now you would have to intentionally dump mana to go OOM and even then you'd have to choose what are generally not optimal spells to spam - like PoH - to do it.
If you are hesitant, try just switching your Talisman to a throughput trinket for now. See if you miss that 128 int. If not, switch 6 gems to SP and see again. Rinse and repeat. If you get to the point where you start to see mana as a real issue (make sure you're using all your CD's effectively), use the talisman as a tool to switch in for those fights you feel you need that extra buffer, and use throughput trinket when you don't.
Unbuffed, I'm running about 9k less mana than you, and my base in-combat regen is 246MP5 less than yours (though I have 2nd solace that makes up about half of that), and I don't use the Insightful meta. I run about with about 300 more haste, and I gem for pure SP. But aside from Lich King, there's not a fight in which managing mana has been an issue, and I don't get the benefit of a mana tide totem or innervate.
TLDR: If mana is a total non-issue, then lack of throughput is. Switch regen options to throughput until mana becomes something you have to be aware of and actively manage cooldowns to maintain. At your level of gearing you'll probably be able to lose most if not all of your int gems for real throughput.