Pretty much the only way to punish a rogue for messing up “vanish or trinket” as you put it, is to land a long stun, or chain stuns, and there isn’t much of that to throw around in arenas if you’re not a rogue though. Although there’s feral ofc.
The rest are limited to stuff like leg sweep and storm bolt, and then the magical stuns which tend to be dispelled so it’s hard to do a setup on a rogue with that, after having found a way to make 'em waste a vanish and trinket first.
DH is probably able to punish it, but they tend to suffer vs. rogues when blur is on CD so that isn’t the easiest thing to do either.
In the end, the one that can properly punish a rogue for messing up “vanish or trinket” ends up being another rogue. Or the ones with stuns somewhat like rogues, meaning ferals, or possibly DHs.
So the question remains:
I mean, sure, you can find those specific scenarios where a rogue has to fail so hard with their defensives and trinket that they just flop over, but with the way they’re designed now, can they realistically fail it? Since not much can punish suboptimal usage of that stuff.
It’s easy to say it’s a failure if they use it for literally nothing, but under realistic conditions where the rogue doesn’t fail it so obviously but just uses it suboptimally, is it even possible to punish it unless you play a rogue or wannabe rogue-feral, or possibly a DH?
And don’t they have 2 vanishes now? Not to mention shadowy duel-escapes.
Also, keep in mind, you have to think of how they’re supposed to get the rogue to use it suboptimally in a realistic setting, it doesn’t just vaguely refer to everything that isn’t the best possible way to use it.
Most classes ends up using what they have to get a rogue to use it suboptimally, and then there’s the question of how to punish them for using it. Which is the problem in a nutshell.