I am having a blast doing a druid/shaman/shaman combination. It was rather easy to learn at the start for keybindings and such and except for shaman having miserable mana efficiency early on I had little downtime. Also eventually gives me the room to respec the druid from feral to oomkin and get the totem caster buffs + the oomkin buff.

I would think though that it is completely dependant on your play style and what you want to accomplish.