Stamina can be considered healing you don’t have to do, e.g. if you take two damaging abilities that would kill you, Stamina means you can avoid healing yourself even after taking two of those abilities. This is only useful in a high end setting where you know the incoming damage. More often than not, Stamina is just a safety net for taking damage. However, Stamina is entirely incidental; do not consider it when comparing gear. You will get plenty of Stamina by gearing properly.
Intellect is only going to increase your crit chance by a tiny amount, not very much throughput gained. The extra mana rarely amounts to any extra healing. If you know the mana regeneration formula, you can account for that if you have 3/3 Primal Mooncloth (you’re 62, so you don’t). Otherwise, it is basically only…
Intellect * 15 * 1.1 * 1.05 = Extra mana and…
Intellect * 1.1 * 0.3 = Extra +Healing
That mana gained can be divided by the cost of a Chain Heal to give you the total healing value of one Intellect.
Essentially, 1 * 15 * 1.1 * 1.05 = 17.325 Mana.
(17.325 / 513 ) * [Total Healing of Chain Heal (Rank 5)] / 2.5 = HPS value of Intellect, plus the value of +Healing from Nature’s Blessing and the crit gained.
Intellect only benefits you once. That is to say, your mana is only increased by a flat amount, and does not scale with fight duration. If the fight is too short, Intellect is useless as you can’t spend any of that extra mana, thus eliminating its value almost entirely. If the fight is too long, the extra mana doesn’t amount to much. This is why Intellect is a weak stat. The fight duration has to be just long enough that it gives you an extra cast, which changes depending on your team’s kill speeds, execution of mechanics, etc.
Mp5 should be measured by calculating how much of an extra cast it will grant you in the time it takes you to cast one heal. So if you have 1 Mp5, Chain Heal’s cast time is 2.5, so you generate half a mana per cast.
Apply the same formula as above, but using 0.5.
0.5 / 513 * [Chain Heal Total Healing] / 2.5 = HPS Value of Mp5.
Similarly, Mp5’s value only exists if you are going to gain any value out of the extra mana. On shorter fights, this value is non-existent. However, unlike Intellect, Mp5 scales with fight duration, making it one of the best stats for long fights.
That said… +Healing is always valuable, even on longer fights, and here’s why: the more you heal per spell, the more you can downrank and the less often you have to cast heals. Almost invariably, +Healing is the way to go.
Here are the stat weights I use on my Shaman for dungeons and long fights (I don’t like to drink during dungeons if I can help it):
Intellect = 0.44
Spell Crit = 0.58
Spell Haste = 1.71
Healing = 0.77
Mp5 = 2.63
Meta Socket = 82.91
Socket = 13.86
On shorter fights (if you can drink after every pull, or it’s a boss that dies quickly):
Intellect = 0.42
Spell Crit = 0.61
Spell Haste = 1.8
Healing = 0.77
Meta Socket = 20.02
Socket = 13.86