Yeah, pretty sure a rogue is not supposed to be able to 100-0 a 550 druid through the first couple of seconds or so of barkskin. There's a horde rogue who I've noticed has done this to me a few times, and he had the "voodoo gnome" trinket, which isn't that high an ilvl trinket. Which suggests that it may be some kind of bug. In fairness, though- I believe he had the berserker buff, so maybe it wasn't bugged.
I'd rather they fix the bug (if there is one) than ban players for simply using a trinket that is legitimately available in the game, at least when it's not completely clear that the trinket is, in fact, bugged. I'm not sure whether the voodoo gnome trinket is bugged, to be honest- this needs to be proven if so.
I think a ban is more appropriate for using the "kidnapped puppy" trinket, which is even lower ilvl than the voodoo gnome one and which summons a clearly bugged number of pets. In fact, I think it is considered an exploit by Warmane, since I've noticed some of the guys wracking up big bg kill tallies with that trinket seem to disappear pretty quickly.
Not sure why these trinkets seem to be such an issue in Warmane pvp, in all expansions, but they definitely seem to be. I agree that they have a really negative effect on gameplay, particularly since they require no skill whatsoever to use.
This is because, with 5.4.8, they increased to 2600 resilience the resilience bonus you get for equipping two pvp trinkets. Maybe this is why rogues still use the pve trinkets- because they can global a target in a stunlock and then re-stealth, not having to worry about their reduced resilience.
Vanguards mentioned this in his 5.4.8 ret guide:
"You want to use double PvP trinket now due to it giving a bonus of 2600 Resilience which is HUGE."
https://eu.battle.net/forums/en/wow/topic/8965476867
I assume (and hope) this resilience bonus is working properly on Warmane. If so, we may have to just learn to live with getting globaled by rogues with pve trinkets, since they are paying a survivability price for using the trinkets. Or at least they would be if you could catch them before they cloak/vanish. :)