Variety of interesting spells
Shaman as a main for pvp is not a good idea. For a good pvp caster, you need to use either doctor or wizard as a main class. Sadly, the seasonal spells lack raw power and aion kinah to make them lethal in pvp.
However, this does not mean you should not level shaman for pvp purposes. The nature magic skill slot offers a variety of interesting spells for pvp that can be subbed easily, since none of them require wands or weapons!
Note that I wont be giving away too much info on pvp, because I don’t want everyone using my build and because pvp is all a matter of preference, in reality. Choose what is best for your build.