As such, healing spheres were not useful pre-patch. There may have been 1 or 2 niche fights or times where they are useful, but as tank healing, spot healing, or ANY major part of our toolkit, they were utterly terrible comparing to everything else. The reason they're so strong now, is their scaling was INCREASED while their mana costs were untouched.
Or for math, they're 1.2x effective.
EnvM costs 30% more than pre-patch, and heals for 1/3 less. Or it's (2/3)/(1.3) or...
53% as effective with ondemand healing (jab for chi).
So by comparison, they look somewhere around 240% more attractive now than they used to, and that is why they are godly.
As for ReM:
While I do reliably get 15 RnM on the raid during AoE fights like garalon/tsulong (despite the complaints I hear from other healers, it seems to spread just fine for me [caveat: sometimes i notice extremely low target counts, but this is like...5% of situations or less]), I also know that they most definitely do not choose the lowest health target. The only time the lower health targets get hit, is when I manually target them. And when theres 2-3 low health targets that need to be picked up? Well I hope someone else notices, because I'll kill the raid by dropping HPS SIGNIFICANTLY to pick them up, when my "smart heal" is NOT being even remotely smart. And that is why I have a problem with ReM not being "smart".
Glyph of Mana tea:
Only 2 things are going to happen;
You're going to have plenty of free time and not be generating enough stacks to matter, and it won't matter if you consume w/ glyph or without.
You'll be global locked and generating as many stacks as possible, as such glyph pulls ahead to 2 stacks/1global comparing to 1stack/global unglyphed. As such, I will continue to prefer glyphed, because unless you do not hit it on CD, it's quite nearly impossible to generate more stacks than you can consume over a fight (barring ridiculously "good" RNG near the end of the fight.)
High HPS rotation: some form of 2 chi generators, 1 spender. 3 globals/2chi, 9globals/6chi.
Add Mana tea 10th global. => 10 globals/6chi.
So you need 1.5 tea stacks to become greater than 2 tea stacks. 1.5*(1+x)=2 where x is crit chance, x needs to be 1/3 or ~ 33% crit chance. I'm barely hitting 25% crit, esp. after hitting the new haste cap, so it will be a long time until I reach that crit chance cap.
This is only during constant chi gen during the entire fight at that rate. If it slows down, or anything like that, then you can almost certainly consume as many charges as you generate (barring absurd RNG).
Ultimately, in high-stress situations, that 10th global isn't going to 'tank your HPS", but it WILL keep your mana stable. On the other hand, your mana will be unstable w/o glyph. Further, because mana tea (at least when I tested) was backloaded, it means if you have to interrupt your tea for any reason, be it tank healing or spot healing or what have you (theres a lot of times where I don't want to be standing still channeling while not healing a tank, especially on heroic modes) then it's an even further waste of globals (just the one global at a time per tea, not all of them, to be clear). Ultimately, the glyph means wasting more time drinking tea and less time using spells, as well as having less ability to react to heal spike damage. Seeing as spike damage is the only reason my particularly tanks ever die, I'm going to stick with the glyph. YMMV.
As for tank healing:
In a competitive H25M environment where the tank not being topped for 3-4 seconds can mean imminent death, MW tank heals were absurdly weak. We were stuck in a catch-22 where healing spheres weren't that powerful yet, and were very inefficient, but our efficient heal is very strong!...however it is a HoT which often averages 80% overhealing in my raids even when i only heal during high tank damage periods.
Now, since I've gained something like 6k+ spellpower, and scaling was buffed to 120%, my HS's average 170k HPS. That destroys everything everyone else can throw out, while being our most mana efficient heal to boot. How much of a joke is that? Yes, now we can tank heal fine, and we will have more mana for healing sphere because we'll be doing less of everything else because those spells are comparatively worse. But pre-patch? No, we were the worst tank healers in the game, by FAR, at least in heroic 25m raids.
Also, healing spheres are a large portion of my tank healing, but ReM/uplift is normally well above them, so don't get "too" crazy with it. Our AoE heals are still more mana efficient. (Assuming low overhealing...which is as impossible to predict as when our HS's get consumed.)