Smite is a 2.5 second cast with talents to reduce it to 2 seconds in the first tier of holy, with Holy Fire being reduced to 1.5 in the same talent. Smites as disc also grant you wings which makes penance and smite hit harder (and makes them virtually free).
Wrath is a 2.5 second baseline cast, but that becomes halved when in Tree of Life (and it's free with talents, able to get your starfire to become instant). They also have moonfire, and insect swarm; two instant dots.
Paladins get a chance to have an instant exorcism proc that costs no mana when they heal. They can also spam it for 70% less than normal. Spammable, low-cost, free damage.
Now, Shamans have:
Leaving out Lavaburst because it requires a lot of set up to hit less than Lightning Bolt.
The issue here is about assisted damage dealing in PvP. Every healer in PvP, but the shaman, has a way to assist in DPS over the long run. As a shaman, however, I don't have that luxury.
I have shocks.. and that's pretty much it. Lightning Bolt takes a very long time to get off for little damage done, and chain lightning not only poses the risk of breaking crowd control but it also costs a lot of mana, has a cooldown and does less total damage (and has less mana benefits) then Lightning Bolt.
If a swap is called (in arena, or in battlegrounds) I don't have much I can do to participate in it. I can't holyfire, or exorcism, or moonfire (or go ToL and spam stupid quick free wraths that proc instant starfires).
- It costs a lot, has a cooldown, isn't spammable and risks breaking people out of crowd controls.
- It actually benefits me by reducing my heals.. but it's on a six second cooldown.
- The target will have died and be waiting for a res before I can actually get it off.
Honestly, why not make Lightning Bolt and Chain Lightning .5 seconds faster for all specs instead of just elemental? Not only does this help us become more of a threat damage wise in PvP (and actually attempt to be offensive) but it also allows Resto to become a legitimate leveling option. I don't see it as fair leaving shamans with sub-par offensive spells compared to other healers. :(