There have been a few ideas (and arguments) floating around the forums about the viability of switching weapons to take advantage of the new changes to Master Poisoner.
The idea behind it is to get a stack of 5 Deadly Poison on your target, then swap to a pair of daggers with Instant Poison on. As long as your target isn’t a rogue with the same spec (-50% poison duration), you have 12 seconds to do as much damage as you can before deadly poison wears off. With 3 seconds remaining on the Deadly stack, switch back to your original daggers to shiv.
While that doesn’t sound like it would cause too much extra damage, the poison proc boost given by Envenom dramatically increases the likelyhood of IP proccing. I’ve had it proc 7 times and still been able to change back in time to shiv Deadly and keep the stack alive. The ideal rotation for maximum DPS would be something like; Weapon swap, 5pt Envenom, Mutilate, Mutilate, 5pt Envenom, Weapon swap.
As usual, this tactic has it’s pros and cons.
Swapping weapons has a GCD, so you need to swap weapons immediately after the previous attack (so the GCD is shared with the one from your attack). When swapping back, you will need to leave enough time for the weapon swap GCD before shiving, so don’t leave it too late (3 seconds before the stack expires should be safe).
As well as having to worry about keeping deadly on your target, you also need to keep an eye on wound/crippling as well. The whole point of this weapon swap is to maximise burst, but all that is wasted if their healer can cast a full strength heal immediately after. Ideally you want to have the healer CC’d during this phase, (well, ideally you want to set this up so you get the kill), but nothing can be guaranteed in PVP.
A Druid’s ‘Abolish Poison’ and a Shaman’s ‘Cleansing Totem’ are your enemies – unless you can dispel/kill them, your stack will lose doses before you can do your second Envenom. Not too much of a problem if you play with a priest, but this can really mess up your cycle/dps otherwise.
Another downside is that you do need to have four decent daggers, but on the good side this means any Master Poisoner who bought the Relentless Mutilator before 3.2.2 will now have a use for it again!
However, all that negativity aside, if you do manage to set up your target with a full stack of deadly and can keep the healer tied up, this weapon swap should get you an additional burst of 4k+ damage compared to not swapping. It’s a situational tactic you won’t be able to use in every game, but anything that can give that sort of bonus should not be ignored.
The macros to swap weapons are very easy to setup; use /equipslot followed by 16 (Mainhand) or 17 (Offhand) then the name of your dagger.
/equipslot 16 NAME_OF_WEAPON
/equipslot 17 NAME_OF_WEAPON
Setup two macros, one to swap to your IP weapons, and one to swap to your Deadly weapons.
A variation of this macro (used by Stealthma on AJ) combines the envenoms/shivs with the weapon swaps. This saves you two buttons on your bars, but does mean you won’t be able to Envenom without changing to your IP weapons. Personally I’d rather have the option of being able to envenom without swapping weapons, but you might find this works well for your own playstyle.
/equipslot 17 NAME_OF_IP_DAGGER
/equipslot 16 NAME_OF_IP_DAGGER
/equipslot 17 NAME_OF_DEADLY_WEAPON
/equipslot 16 NAME_OF_DEADLY_WEAPON
You will need to press each macro twice, the first time to swap weapons, the second to envenom or shiv.