If you practice Karate, Kata should play a large part in your training. You should never change Solo Kata, Solo Kata should change you. However, when it comes to Bunkai, I think Kata gives you many options. That can mean you don’t have to follow the sequence of the Kata. You could even mix and match Kata’s to suit you when used in Bunkai or kumite drills.
If Kata Bunkai is prescriptive it may be useful to enhance your skill base and understanding, but will not necessarily be effective for real conflict or free combat.
You have to feel able to use your techniques naturally, instinctively and freely. You should be confident they would be effective. Many moves and techniques in Kata if used as they are within the Kata would not work, they must be ” adapted ” to make them effective. Ultimately you must test your ideas robustly against a non-compliant opponent. This should be carried out in a controlled manner so as to prevent injury.
The way you should perform your Kata in relationship to Bunkai/Kumite has to be your own. It needs to suit your individual abilities both physical and mental. If your instinctive responses are ineffective, you must train to alter them. Having a good Instructor/training partner is essential. also correct training in Solo Kata can bring about positive change