put a feedback link at the bottom of every page of family trees to provide an easy way for people to make suggestions or comments about that page.
I assume you mean feedback about that particular page of family information, not about the web site itself or anything to do with Family Search. That link is already there and brings one to this community. But rather to have a place to put suggestions about how to improve the data for the family on that page? If so, this is can already be done in notes under the Collaborate tab on everyone's detail page. It doesn't seem to be used very much, however.
If a more prominent button were there, what do you picture as being the result of using it? Sending a message to everyone following the person? Sending a message to everyone that has ever contributed to the record? Just getting posted as a note on the page which would probably still just be a note under Collaborate?
If you expand your idea to include reasons for it, what it would look like, how it would function, and what the end result and goal would be, it is more likely to catch the attention of the site designers and programmers.