I am all for the larger image to be centred at the top of the page for the item view, however it's just not practical for category view to have so much wasted space. The only way to have this is currently is to put a smaller image in the text and switch the image to "hide" in the category settings. Although when I  do this I can't hide the smaller text-wrapped image on the item view page.
If anyone knows a workaround that already exists that would be great, otherwise I think it would make K2 a much more complete package by including it.