Well, unlike the other stuff, like startup, iexplore, disabling services can really break your operating system. There's a reason for putting the Services application in the Administrative Tools: because it's meant for real IT administrators. Of course, there are many Windows users who probably know what they are doing (including yourself, I presume), but since CCleaner is an end-user application, simple PC users might disable critical Windows services without knowledge thereof (and flame the forums afterwards, of course).
Also, CCleaner was successful due to its simple interface. If you implement a Services module, you need to increase the complexity of the interface, since you absolutely need information about the services you're about to start/stop/disable, and reasons for it, too. As a comparison, I believe the description given in the Administrative Tool isn't enough. In that case, CCleaner would lose its beloved simplicity. Unless you can come up with a better solution