I wonder how did you calculate the raid dps benefit over the personal dps benefit. I'm still not convinced that it's good to go for 4T10 or any T10 since there is 0 spirit on them and the +hit items have +crit too, so all 5 pcs are terribly itemized for demo.
Most of them weren't actually far off from best in slot (the head was esspecially close). Also estimated uptime of 4xT10 is ~39%, which means ~3.9% damage. At 10k dps, thats about 390 DPS. To make up for a difference like that your replacements would have to do that + the DPS bonus from 2xT10. It's a given that atlest 2 of your alternatives your alternatives will need to be heavy on hit (=0 spirit), so you're basically stick replacing 2 items with spirit gear and 2 items with hit+haste (ideally) and you somehow have to gain in the area of 500 dps from that- you just won't.
The T10 bonus is simply really good, and although the items have no spirit, you'd only be able to pick items with spirit for 2 out of 4 slots anyway because spirit+hit items don't exist in ICC. Lets say you replaced the crit on gloves/legs with haste, and the crit on head/shoulders with spirit. You'd gain 212 haste, 204 spirit, and lose 416 crit (Mind you, items with those stats dont exist)- resuls: 111.36 personal dps from crit->haste, 27.21 personal dps from crit to spirit, 180.06 raid dps from crit->spirit. Total: 318.63 DPS, meaning you gain less DPS than you lost from losing the 4 piece bonus alone- yet you'd also be losing the 2 piece bonus.
Scale factors: SpellDamage=1.7642, HasteRating=1.6812, Spirit=1.2893, CritRating=1.1559, Intellect=0.4449, Stamina=0.2684
212 Crit->Haste: 212*(1.6812-1.1559)=111.36 dps
204 Crit->Spirit: 204*(1.2893-1.1559)=27.21 dps
204 spirit rDPS: 204*0.59*1.1*0.1*8*1.7=180.06 dps
Explanation of the bottom one:
0.59=glyph of lifetap+felarmor*demonic aegis
1.1=blessing of kings
0.1=demonic pact only takes 10% of your spellpower
8=8 caster dps
1.7=average caster dps spell power scale factor.
So even if you swapped those stats around in the most ideal possible way, you still wouldn't gain rDPS.
There's 1 caveat; I don't think we're 100% on wether or not 4xT10 has an internal cooldown/how long it would be if there is one.
Also a footnote; although you could argue for higher number of dps casters/average spellpower scale factor- and you might end up with more rDPS than the 4 piece bonus, theres 3 more things to consider:
 These items don't exist.
 You'd also lose the DPS from the 2 piece bonus
 The value of spirit/haste would drop relative to the value of crit as a result gaining more of them and losing crit.
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