Shaman's and Druids do make for a nice duo and really you can go out and have fun without the reliance of any kind of merc help. Both of these classes are able to solo well, and each can compliment the other when grouped up. There have been several times where I would group up with a druid friend of mine on my shaman and just go out to have some caster fun. The way we would do things is she would grab the mob(s) and would be kiting the thing along and I would be dumping all of my DoTs and Nukes into her particular target, and dog dog would be running along hitting the mob and proccing panther... this works very well in a lot of zones, and in this case everything I was tossing on the mob stacked with everything she was casting as well.
If things got to hairy... there was almost always the ability to VP or root off a mob or 2, and just focus on 1 for the kiting portion. One thing to keep in mind is not to drop the big nukes on the druid and focus on their line of DoT spells if you are root rotting. If they are just snared, you can drop all the big nukes you would like and the mobs go down very quickly.
From a buff perspective, both classes bring several very good buffs and utility spells to the table. There are a couple that overlap, but mostly these will work nicely together. If you go down the path of using mercs as well, the cleric stuff will also stack with the druid and shammy buffs. And really... you have a lot of healing to keep up almost any tank merc. The only downside of the combination in my opinion is that you lack a reliable second tank. The shaman will take hits better than a druid in most instances, but if you have to go to toe with a mob... you have your merc... your dogdog speed bump, and most likely an evac.
As always... it is just a game... have fun out there....