Since I have some free time right now here is what is needed for boomkin PVP in BGs from what I know (I don't play boomkin often, I'm usually feral so if I'm wrong somewhere someone can correct me please):
1. On mouseover, spread both Moonfire and Sunfire, Depending if you are in lunar or solar state, either moonfire or sunfire will have precedence over the other. Also possible to make a check for example if the target currently already has moonfire/sunfire applied and the DoT > 5 seconds don't cast. I'm not certain but if there is another boomy it could prove troublesome because if they have their dots applied yours would not get applied. I'm not sure if there is a way to get around this? Possibly adding a radio tick option so it can be turned off manually by the user.
2. On target cast Wrath/Starfire depending if you are in lunar or solar. Whenever starsurge procs, cast it asap on your current target.
3. A hotkey to cast both solarbeam and Ursols vortex on mouseover.
4. The usual 1 hotkey for setting up mushrooms, and when 3 mushrooms are up a fourth press of the same hotkey will detonate them.
5. Cyclone hotkey logic on focus, if natures swiftness is up, use it for an instant cyclone otherwise cast cyclone.
6. Root shifting just like the pve option.
7. Healing, when moving and hp bellow a certain threshold (this threshold should be in pqi) use rejuv, otherwise if standing still use either healing touch or whatever other heal is available to a boomkin (honestly I forget what healing spells each spec gets since MoP separated them into their respective specs.) When bellow a certain threshold use defensive cooldowns, barksin etc. If present, use Healthstone at a certain threshold for instant heals. Also if natures swiftness is up instant healing touch when bellow a threshold.
8. AOE Burst button/rotation cycle. Casts Incarnation, natures vigil, celestial allignment, pvp trinket etc offensive cooldowns, during this cyclone when using mouseover only apply either moonfire or sunfire, because when you apply one in celestial allignment, it automatically applies both dots to the target. During this burst, you want to apply starfall three times in a row:
HOW TO STARFALL 3 TIMES IN A ROW IN 5.0.4 | Boomkin Cooldown Usage | World of Warcraft PvP - YouTube Afterwards when the burst is done, the user can switch back to normal mode.
9. Possible support for different symbiosis abilities depending on the class you choose to do it with?
Symbiosis Breakdown: What Abilities it Brings to Each Class - Wowhead News Only the defensive ones would really need logic, for example bellow a certain threshold cast antimagic shell. Can do some creative stuff here if you are up for it.
This is what I can currently think of, I'll edit this post if anything else comes to mind. Also others input would be welcome as i havnt done boomkin pvp in some time.