Like Noressa has been saying, and I said a couple pages ago, if you can get enough haste to achieve 5 casts per cycle then there is plenty you can do other than lifeblooming 5 targets. Consider a 3-tank scenario, which is part of the strategy on a pretty large number of encounters: right now the best we can do is lifebloom them all and rejuvenate two, and this saps all of our GCDs. If we want to battle res someone, innervate someone, etc, we have to let a rejuvenation drop for two cycles. With 5 GCDs per cycle, we get two benefits: we can do more healing by keeping up lifebloom and rejuvenation on all three, and we have one free GCD every two cycles to use on innervate or NS + Rebirth.
About the spirit changes on the PTR, I spent a little bit of time messing around with the formula people are shaking out in the
Intellect -> Spirit Conversion on the PTR : Theorycrafting HQ thread (the one that looks like
Regen_mp5 = 5*0.00932715221261 * sqrt(Int) * Spirit). I don't plan to update the first post until the changes go live but if that formula is accurate then there are a few implications that stand out:
I haven't been keeping up very well with the new items in 2.4 (just the new mechanics) and so I'm not sure if there are any sweet new consumables or gems that invalidate some of this. As usual these calculations all assume Living Spirit and Blessing of Kings. Also, keep in mind that this is all based on a formula that was theorycrafted on a test realm that has been up for only a few days, so it is obviously subject to change!