Lets face it - no martial art is effective if not taught effectively. Shaolin Kempo isn't bad, it is just taught by a remarkably large number of worthless people. This has happened in every martial art. Find a great teacher - and it won't matter what you study, it will be a good thing. Granted, some arts teach an area that might not be in your interest: for example, not everyone wants to learn ground fighting, therefore they don't want to study Brazilian Jiu Jitsu. It doesn't matter if someone thinks BJJ is the ultimate, or is absolutely necessary. The truth is, if you don't like carrots, you won't eat them no matter how good they are for you. .... but - it doesn't mean you shouldn't eat any healthy food! Studying any martial art is good, and the individual can eventually make it better. However, it has to have the foundation of a good teacher.
The pronblem with Kempo/Kenpo - is that each faction has "over" promoted everyone. Just because a person is a 5th degree black in Kempo, means NOTHING. Take a look - most have never studied with the person who promoted them. That said, other arts are not guiltless in this either.
Bottom line - stick to what you have as a base, improve it yourself regardless of the quality of what you have (Y-O-U can make it better). Be very careful of ANY organization in the Kempo arena - most are garbage, and only provide an opportunity for the worthless to hitch themselves to a known name. In other words - Do your homework.
It's times like this I wish I could punch people through the monitor...and possibly also rape them.