If you want to fill in group role and want to solo at the same time, i guess the hybrid classes will be suitable

I rolled my shaman without knowing i had to heal so much but i still manage to solo well by killing mobs my level without needing to stop. This is my experience when BC was released because 60-70 have no downtime for me except when i get gank or lag issues. I specced enha and easily got to Maghar exalted in just one night killing ogres near Telmaar cause i have no downtime even i was only about level 65 at that time in Nagrand

From 1-60 as a shaman, i cant give my opinions anymore since it will be different from the time i level. I used 1H+shield when solo to level but i guess new players will be using dual wield