In any kind of business deal, a middleman can be either a blessing or curse. In the worst cases, he or she might gum up the works by making communication with vendors difficult and charge you a premium for the privilege of being inconvenienced. In the best cases, the middleman's expertise might save you time, money, and aggravation, and it could be well worth whatever margin he or she might apply to the deal. IT has historically been rife with middlemen of both varieties. Whether you're talking about VARs, MSPs, or other different kinds of businesses, repackaging and reselling others' gear and services is an enormous and well-entrenched industry.
It would seem that the cloud is a huge exception to that model. After all, the nature of the cloud is such that you're supposed to be able to sign up and instantaneously have the services you want available to you -- a reality that lends itself well to the direct sales model. However, I believe that resellers of cloud services or cloud brokers will have a great deal to offer as the cloud industry matures over the next three to five years.
Today, the average enterprise might use a handful of cloud services: perhaps Salesforce.com as its CRM and a few Amazon EC2 instances to host a public website, maybe a hosted email or antispam platform. It's relatively clear at this point that the future will bring wider and wider adoption of cloud services as a means to do business. However, just as today's enterprises aren't getting those services from one cloud services provider, those of the future won't, either -- the difference is that there will be far, far more of them, and their services will play a much more critical role in the enterprise's success.