Cata Destro was PoS. Finally, something me and Xel agree on!
But if you're looking for an example of a 'good place' for a Destro pvp model, honestly the Litch King one was pretty great. CB/Conflag/SearingPain was a potent combo every 15-30sec. Immolate dispels sucked, but at least you had meaningful damage if you could set it up properly. Not saying we turn back the clock, but I feel like the concept of that model was sound with a few tweaks to the interaction with immolate.
Right now, we either are gods for 8 seconds if we are able to pop CDs and land a crazy CB - or we are able to be completely ignored if DS is on cooldown. It's really not a fun model. Destro should be able to pump out dangerous burst every 30 seconds (like our piers), but it shouldn't be able to global someone once every 2-3 minutes.