Hello again Amajed!
I would say that
Foul Gift of the Demon Lord is superior to
Bottled Wishes. If you compare the two items, you get the following stats,
- from
Foul Gift of the Demon Lord: 383 Intellect and an average Mastery Rating gain of between 459 and 510 (some people say the Internal Cooldown for the on-proc effect is 45 seconds, other 50);
- from
Bottled Wishes: 381 Spell Power (15 second on-use effect on a 90 second cooldown) and 458 Haste Rating.
For your Elemental Shaman (as well as for any caster), Intellect is vastly superior to Spell Power, so this makes
Foul Gift of the Demon Lord the clear winner (the Mastery and Haste gains are similar in value, so they should not be used to determine the relative values of the trinkets).
Regarding
Threadlinked Chain and
Opal of the Secret Order, you need to understand that, as a DPS caster, you do not get benefits from Spirit in the way healers do (i.e., it does not increase your mana regeneration while in combat). As a DPS caster, your mana regeneration while in combat is equal to 5% of your base mana (about 1171 MP5).
Therefore, you need to consider that Spirit and Hit Rating are exactly the same for your Elemental Shaman. So the only factor on which you are going to base your decision is which of the two items provide the best second stat. As you noted, Haste Rating is better than Critical Strike Rating, meaning that
Opal of the Secret Order is the better choice.