A bad student blames the book or the noise or something other than themselves. Simple.
When you are as good as your teacher then you may, just may have the right to criticise.
Right! A student's work is to constantly practice with the guidance of his teacher, critisism and excuses will get you nowhere, only hard work will lead you to actually learn the art. There is no level that cannot be achieved (even o'sensei's) if one is training seriously, aikido is a difficult martial art, not a simple recreation activity. As for the critical mind, i would say that it is better if one has an OPEN mind, and of course you can't be critical about o'sensei. It's not a matter of religion or cult. He has proven his value long before we were born, so if we want to achieve his skills we'd better pay attention and practice! I like the way you see it, good post! Good luck with your practice...