Hey, I'm from Ask Mr. Robot and wanted to point you to a page most people don't know about
:
http://www.askmrrobot.com/wow/trinkets/priestshadow
We take every trinket and simulate the amount of each stat you get from procs. That means we model out the ICD and proc rates, simulate a ton of fights, and see what the average uptime is. We then assign the average value of the proc stat to that trinket, if that makes sense.
Proc comparisons across each trinket:
Flashfrozen Resin Gobule: gives 816 Int on avg
Mithril Wristwatch: 911 Spell Power
Relic of Yu'lon: 851 Int
So you'd be getting 35 more Int from the Proc on the Relic compared to the Flashfrozen trinket. And you'd be trading Int for Spell power on the Proc by replacing the Wristwatch. Now, you get a 5% Int buff passive and a 5% Int raid buff. So that 851 Int Proc on the Relic of Yu'lon ends up giving you 938 Spell Power. Then if you factor in that the Relic also gives you 956 Int (or 1054 after the 2 Int Buffs), it seems like a pretty nice upgrade.