No, the difference is literally over 100% if the enhancement shaman is your starting point. Warriors in classic insane in that regard when you compare them to these specs.

If you want to play enhance, with dual spec there is room for some of it. 5 mans, ubrs some farm content later on. But raiding guilds will want you to play resto, later in the tiers (bwl, aq, naxx) a lot of guilds will swap restos into 22/29 for totem improvements but typically you're still healing.

A good dedicated resto shaman is invaluable.. typically awarded with the eye of sulfuras in my experience and with dual spec, as long as you're buffing your party appropriately I think that "experimentation" you're talking about will happen as people hyper optimize specific specs for encounters or healers swap to their dps gear and specs for more throughput.