Glimmering Naaru Sliver

This trinket is amazing. Although it has been belittled and heavily criticized by the general healer community for its inflexibility and unreliability, I strongly beg to differ.

I think as time goes by, people will realize that this trinket has been denied the kind of theorycraft that it should have been subjugated to in the first place. First of all, the trinket has 119 passive healing, in other words in terms of raw healing, Glimmering Naaru Sliver is identical to Redeemer's Alchemist Stone and Mememto. Here comes the critical exposition: how much Mp5 does the trinket offer? In my opinion, this trinket is better than Memento, and may even be better than Redeemer's in rare circumstances. Below are my calculations:

Assuming the trinket is used on the 2nd and 7th minute of a 10 minute fight and is given full grace, the trinket gives a total of 4000 mana.

MP5 for 8 ticks per usage = (4000/10/60*5) = 33.33
MP5 for 1 tick per usage = 4.17
MP5 for 2 ticks per usage = 8.33
MP5 for 3 ticks per usage = 12.5
MP5 for 4 ticks per usage = 16.67
MP5 for 5 ticks per usage = 20.83 <-- Better than Memento
MP5 for 6 ticks per usage = 25
MP5 for 7 ticks per usage = 29.16

I did mention that it could be better than redeemer's, but this hypothesis requires some annoying assumptions. That is, the trinket has to be used twice in 7 minutes with good timing.

Mp5 for 8 ticks per usage: (4000/7/60*5) = 47.62 <-- Better than Redeemer's
Mp5 for 7 ticks per usage: 41.67 <-- Better than Redeemer's

Explanation of the trinket mechanics:
1. When clicked (activated), the user casts the Evocation spell (channelled). The name of the chanelled spell is exactly as said, "Evocation". The player also receives an Evocation buff icon on the buff table (during the cast) that is not categorized as magic; I assume it's for an indicatory purpose.
2. Without any spell haste or casting speed modifier, the Evocation cast is 8 seconds and ticks for 250 mana at each second for a total of 2000 mana.
3. The channelling spell is subjected to melee and spell pushback, however Improved Concentration Aura gives it 50% resistance (35+15) to pushback.
4. The cast cannot be Silenced (Arcane Torrent, Silence, etc) or Counterspelled (Counterspell, Spell Lock, Pummel, Kick, etc). Kick and Pummel can cause pushback due to damage dealt.
5. The cast can be cancelled at any time without any penalty to the mana you have already received.
6. The trinket is placed on 5 minute cooldown upon use.

Interesting pointers:
1. Each tick of mana does not place the caster in combat. After 6 seconds of usage the user is guaranteed to be out of combat, ceteris paribus.
2. The caster will receive out-of-combat regen after 5 seconds of the channelling.
3. Some theorycrafters suggested inputting the base mp5 you get while channelling the trinket because the caster does forfeit healing (or dps) during the channel. However I have not done so because of the impurity of the calculation.