I suppose you could, still I would not limit myself to only pvp.
That said we have some people who rank with 0 enchants and blue/ questing gear in offslots now, and they make it work. So you dont have to put in a whole lot of effort, a little goes a long way (like professions; engi/mining and the package there).
I actually did the respec 2/4 times a week. Was not as bad as it sounds honestly, just raw mob/ boss gold paid for most of it then id cover by selling the herbs I didnt need much (plauge/groms).
In terms of shaman:
As you get better healing gear eventually you can heal in 30/0/21. Dont expect ppl to allow it for progression or speedruns, but it is not horrible. You miss out on 10% healing/ mana tide and hw cast time (but its nearly all spamming ch anyway).
Its not that noticeable tbh, mostly gear based shaman healing. Infact you can beat geared healers that are deep resto (not that healing meters means much). The main thing is you may have to spam more mana pots/ runes.
In terms of gear Its kind of rough getting full bis as a mostly pve unviable caster. But your second best options are pretty strong too.
Long term I would aim for (naxx excluded):
3p 2.5 set + 2p r12 (legs+boots), jeds + zg trinket
(t 2.5 is free as sham, its also a good healing set.)
/
Or if Aq 40 is also all out: T2 head / legs | mc shoulders | zg chest/bracers
For neck there is a very very strong option from the aq 20 boss head quest. Its not far form twin emps / naxx / rag neck. / then nef head stam neck is also strong
Rings: zg ring/ silithus boss are easy pickups. Then eventually Aq rep caster ring becomes very good.
Cloaks: ony cloak is not bad, besides that in bwl you can possibly pickup a stam/sp cloak (that is your second best; this has no hit on it so for pve is just worse than many other options).
Bracers: burrowers bracers in aq 40 (stam+sp, for pve theres a better sp+hit silithus badge reward). Or if Aq is out Zg rep bracers are decent.
Gloves: Aq 20 mail option/ ranking blue pvp option (has spell crit) rank 12 gloves has melee crit; its very amusing. Otherwise cthun cloth / bug trio leather or kalimdors, but likely more contested.
Belt: firemaws cloth belt possibly, how contested that is will vary, may have to live with a DM dung option for awhile.
Shield : just whatever has the most armor. Your healing shields are very viable. Aq > mc > bwl healing shield.
Crafting the aq silence shield could also be an option, depending on the prices.
Wep is probably the hardest; really should get lok amir or rank to 14. (End of dreams> lok > r14 dagger). Hand of edward could also be used, but its rather rare. Before then the aq 20 quest reward is good.
Ah and yeah for libram/totem there is only one actual option, the boe world drop lb/cl dmg. As that is nearly all of your dmg, shocks scale very poorly. Could be expensive sadly. Checking the neutral ah would be smart there.
All in all ends up pretty darn strong, not far from the sp you have in a full bis setup. Its mainly lower crit - but we do get 11% crit from talents.