Remove the ability to spool up CnD before stealing. (Anet needs to fix the culling/rendering issues). Problem solved.
If you stand there on a CnD (and do nothing) when the thief is right there behind you, then you deserve the damage (if said traits/abilities are on CD, then it you would’ve eaten the damage anyways)
Basilisk venom can now be broken by various traits/abilities, so you can’t say you had no chance.
If you’re in a mass of fighting, and it happens, chances are, any other profession could’ve taken advantage of the confusion sown by so many around you.
I’ve run both a condition/survival build and a glass build, and while it’s a lot easier on the survival build, it’s definitely survivable on a glass build if your CDs are available and you’re paying attention.
Footnote: I’m not advocating that thieves aren’t OP, underpowered, or just right. That’s a post for another topic.