I think co-founders are most useful when you have a similar vision but bring different expertise to the issue. I agree with what you are saying though, that you

I think co-founders are most useful when you have a similar vision but bring different expertise to the issue. I agree with what you are saying though, that you should have similar values and vision, but then want to discuss the implementation from different perspectives. It's kind of like having a mini focus group or think tank. Those different understandings of the issue are important to come to the BEST implementation and to avoid groupthink.