T15 trinkets for T16 progression

[Minoan]

Assuming RPPM(and especially feather) scaled down now, can someone who is having all these precious treasures on PTR or at least had some experience with them share their feelings? By that I mean the possible trinket list for 2H Frost, Unholy and DW.
I've heard some very bad feedback about stack rate of Gaze and Primordius, therefore ICD T15VP trinket and possibly Feather(even nerfed, still with a big proc rate), but I night be wrong and do not have Spark as well.
Possible blood trinkets(if they are changing as well, honestly was not paying too much attention on tanks' trinkets) are highly welcome.
We're assuming Heroic level trinkets because LFR/Normal versions could be replaced with new LFR/Flex trinkets fast, but 543-549 trinkets may remain competitive 'till some point

[Darkfriend]

I am actually wondering if 2/2 SPA trinket will beat out 2/2 feather for UH.