I've never been at this much of a loss for how to effectively fight against a PvP meta. I play PC/NA CP PvP.
In the past, I'd effectively counter SnB "hold block and heal" with DoTs and Defiles, both of which have been pretty much deleted at this point. There's still a handful of unblockable stuns, but even on various flavors of full damage spec Medium SDK builds I'm not exactly dropping 35k burst damage with Fossilize or Turn Evil combos before they break free and block heal to full health. The old Dizzying Swing stun would open up a good window if you caught them with their block down, but now I'm not landing an unblocked followup medium attack for the stun unless they're really not paying attention (or they're a literal potato), nevermind the fact that Off-Balance is redundant with Tactician CP making it a waste of the ability's power budget.
Sustain was nerfed in terms of dealing damage, but untouched when it comes to playing defensively. I haven't seen anyone run out of resources blocking or healing unless they're being zerged (or they're a literal potato), while I've definitely lost fights to players on damage builds with back bar SnB because I ran out of resources trying to damage them (a new experience, I'm sure I can "adapt" to this part, but frustrating still). Resource poisons have poor uptime and don't affect block cost anyway. The saddest part is that I was consistently able to run perma blockers out of stamina back in the 1.X soft cap days, even though you could regen stamina while blocking. Achieving high SnB block uptime in PvP is just trivial now, both in build and skill investment.
I guess I'm hoping that I'm missing something, and that it's just a L2P "adapt" issue on my part, but it looks like we're in for a tedious 3 months of block, heal, and zerg.
PC/NA || CP/Cyro || RIP soft caps