I quite enjoy the DLC, despite my misgivings about its overall price (the DLC civ packs totalled = $20 or so, which is quite pricey per civ if you think about it). The scenarios are generally enjoyable, if a bit bland. Some, such as Genghis Khan, are quite challenging on the higher difficulty levels, and you race against time, which naturally puts some stress on you to push forward with your strongest strategy, rather than just rifle and cannon rushing your enemies for a Domination win (which I do all the time in SP when the enemy foils my attempts to win by culture). I quite like the 1066 scenario in the Denmark DLC, since it comes with its own unique units and improvements (Norman motte and bailey castles! YAY!) and each side plays fairly differently. If you're playing as Harold Godwinson, you control all of Britain, but also have to fend off persistent attacks from 3 rivals who invade by sea, which is both frightening and exhiliarating. Paradise Found (from the Polynesia DLC) is more a map for the explorer, and you can get lots of fun if you're like me and enjoy sailing across huge expanses of blank ocean, looking for New Zealand so you can get that Steam achievement, lol. The Conquest of the New World is probably the most dull scenario, but there is a difference between each faction, and a race to be the first to get your caravels to China, so that keeps it somewhat lively.
The civs themselves are decent, I'd say Inca, Polynesia and Denmark are markedly different. Spain is interesting but not as much of a game-changer as the others, particularly since natural wonders are rare and don't often fall within your borders (usually the city-states get them, in my experience, and some are out in the ocean like the Great Barrier Reef or Krakatoa).
That said, it's quite likely the DLC will appear in a cheaper bundle in the future, since that's the way of these commercial enterprises. Other games that had DLC also had similar pricing schemes. If you don't want to hold off waiting, and you're bored with the game as is, buying DLC wouldn't hurt.
Just cut back on going to that pricey restaurant you were going to eat dinner at, and you can easily afford all the DLC and not feel bad about it.
On the other hand, if you don't really care too much, it's not a bad idea just to play other games until Civ V's DLC comes for a much cheaper price.