my thoughts on that:
i can not agree more about visulising an oponent when doing kata - its a staple part of Iai when doing waza and it is something i try and incoperate into forms, at the moment i do not know my katas well enough to do this - but in time i will do.
now coming on to noddy bunkai - yes and no, to my mind the kata is a set pattern to enable you to train techniques on your own, and to enable quick, set efficient ways of teachin principles - the kata, like the sensei is there to guide the student on the path - now i do like the idea of then coming up with your own bunkai as practicing, this then enables the student to walk the path in his own way once guided - in fact the first style i did would not actualy teach you the bunkai to any forms - if you asked, the reply would be inveritbly be "what do you think it is" unfortunatley i was to young and unexpirienced ot understand the basis of this lesson, and it was never explained - which is why i think having proper set bunkai for kata, as well as kata itself is important as part of (but not the whole) of any training regime - as it starts you off down the path and clarifies it for you - once you are ready you can step of this path and forge your own - this to my mind is the key to all martial arts....but many also say im a raving lunatic, so feel free to ignore my ramblings.