It'd be nice to be able to change the default email text:
I'd like to recommend you the following page...
either via filter or a plugin option. especially since this isn't really commonly used english. in english the correct way to say it would be
I'd like to recommend the following page to you...
otherwise, i think this is almost exactly what i've been looking for as i needed a shortcode (which you should add to your instructions page as i doubt most people know it is there hidden in the code) that would let me specify the URL i wanted to share.
Please insert here the email addresses separate by commas
is also improper grammar/typo. should probably say:
Please insert the email addresses separated by commas