The term "freestyle" has too broad of an interpretation. For some "freestyle" systems, they'll simply take the basic techniques of two systems, and combine them into one, while others will branch out into more than two systems. Regardless of what method they choose, though, they generally don't strive to have a deep understanding of a specific art. There simply isn't enough time.
The better question is, for what are you looking? If you're seeking a mastery of an art, then jumping all over the place isn't going to get you there.
In most systems, if you're just getting to the level of Shodan, then it simply means that you have a decent command of the fundamentals, and are ready to take on the more advanced training. If you quit on the system at this stage, then you will simply have never had a chance to experience a greater in-depth knowledge of the art in question.
If you're simply seeking competency in multiple arts, then perhaps it could be right for you, depending on the specific application.
For some people, such as mixed martial arts folks, they can get to a decent level just by having such proficiencies in multiple arts, if all they want to do is compete in the ring. Someone can study the fundamentals of boxing and wrestling, and be a pretty competent fighter at the lower levels in a relatively short time.
My opinion is that in the long run, it's better for someone to have a deep rooted understanding of a single system as a starting point. From there, he may very well be able to properly incorporate other systems' methods, since he'll have a decent understanding of how the human body works, etc. Some people might point out that Bruce Lee made his own system of Jeet Kun Do, which combined multiple arts in a "freestyle" fashion, but it's important to remember, that he was already an expert in Gung Fu, and that he was a one of a kind individual...
