Putting anything to any other place then to the plugin page is for me one of key signals for automatic deletion of the plugin (the other signals are errors shown with debug=true, using of non-wordpress-standard look, feel & functions etc. I also hate creating custom top menu level, unless it is really complex plugin that is used so often and with so many different pages, that it really needs it (but it is not automatic blocker for me, i just sometimes delete their menu)