With my numbers until you can get T6 level gear, (oddly enough) it goes roughly like chest, hat, shoulders, gloves, pants. In 2.3, the engineering hat becomes more viable, and so you can swap it with the shoulders. It's a bit of a muchness. The T4 pants are certainly the weakest of the pieces for dps.
There still issues with a lot of random epics, because they don't have agility on them, so while Bloodsea for example might be better than t4, it's only marginally so, and mainly due to item level and the wasted stats on the t4.
ETA:
There's no section for bear trinkets. Just that comment in the living root entry.
[Badge of Tenacity] is probably a better trinket to use if you're switching because it's activateable.
As I understand it, lacerate crits will only increase the base damage component of it rather than the bonus threat, and more importantly, that initial application can be blocked, which because it's doing low damage can result in the whole hit being blocked and no threat applied.
You can't completely ignore the DoT component. Fully stacked, even at a 20% threat modifier they do in total about the same threat as the initial application. That's why you maintain it on mobs that are vulnerable to bleed effects.