I don't see any current, relevant information about gearing for 80-89 PvP anywhere in this bracket forum. So the OP's question stands. I, too, would like some enlightenment on the current thought of PvP gearing for this bracket at different levels, the current scaling of gear and health-per-stam, and the reasoning behind choices made.
After my WoWhead research to retool my 80, I'm pretty happy with my resto set other than needing to replace my gloves and wrists with mail variants (I'm going to go with the PvP gloves for the extra 5 yards range with shocks and shears) for the all-mail 5% int bonus.
Things to note: Blizzard claims that PvE set bonuses will not work in PvP. I don't know if that's an endgame thing, but my ICC 2pc bonus works fine in skirmishes, which is why I'm using that gear.
Also, remember that cata gems (and newer) have item level requirements. Older gear has more sockets, but depending on what stat you want, it may not provide what you're looking for. Mastery remains my top stat for my resto shaman, but since mastery (and associated gems) didn't appear until cata, getting MoP gear with mastery appeals more than wrath gear with sockets.
Related to that, mana regen remains through the roof for my 80, so spirit is absolutely useless. I "stepped down" to an ilevel 300 feverflare ring to get mastery and haste, because the remaining 308 rings (after I get Anthia's ring) won't deliver as good of a stat combination for me.
Once scaling comes to skirmishes, I really, really want to know how gear scaling will work. Thanks to the gear squish, there is no stat difference between starter ICC tier gear, midlevel ICC gear, and heroic ICC gear. However, we've noticed in the lower level brackets that lower ilevel gear actually scales *better* than higher ilevel gear. Therefore, it's possible that gear with an item level in low 200s could end up BiS thanks to scaling for 80s. We need either some battleground pops, or info from someone who queued an XP-on battleground and can deliver some info.
Looking forward to more information all around, for sure.