Hi Chosen One,
If I understand this right, you have been in this school for 4 years, a 2nd brn?
In my opinion, I would stay with the current school, read some extra information on various Katas you think might be missing, view some on video, talk somemore to your instructor, ask if there is more you could learn and if the instructor will assist.
You have been there for 4 years and very close to your Black, get your Black.
It sounds like you are second guessing yourself and starting to think that you want more Kenpo. Get the certificate for your work and accomplishment so far. If you are still wanting, then seek further.
The situation you will encounter is this... Being a brown you will be demoted right away to a lessor belt just on the fact they will want to impress on you that the school is better then from where you came. If it is, or not.
This may happen even when you have your Black, but you will have accomplished your goal in getting your Black, you should work through this moment in time and indecision, and stay with the school you are in.
All the above is based on if you are happy, like your instructor and are learning new stuff. There are some schools that will not give out Black belts, because they do not have the ability. Is your instructor a certified Black Belt? Has he promoted others into that position?
What is the name of your Martial Art, each time you work out, do you feel you are learning more? Do you have a contract with this school? Is it month to month? How often do you train?
These are items that weigh in on the decision if you want to stay in Kenpo.
After getting your Black, You can go to a different art and see if it will supply what you feel is lacking. You could go into FMA, learn sticks, or BJJ. There are alot of Martial arts that can work well with kenpo, Aikido is another that comes to mind, JKD, on and on....
There are many avenues, but I think you should get your Black in the school you have spent 4 years in already.
Good Luck, Regards, Gary