1. If it's a hobby site, then the bottom line is that the site admin believed it was a good suggestion and he or she decided to make the change. Who cares if the idea was presented by a new member or an old member?
If the membership raises the issue, just let them know that you're balancing the pros and cons of making changes based on what works best for the site/community overall.... and leave it at that. There's really nothing to be gained by "appeasing" individual members or any particular segment of the group to this extent.
2. If it's a commercial site... well then, it's still the exact same thing. Each option that comes along needs to be evaluated on it's own merits. That's got nothing to do with personality issues, popularity contests, or catering to people too much just because they complain alot.
The owner/admin has to make really tough choices from time to time. Being able to introduce a necessary change and handle the announcement along with any possible backlash is a skill we all need to develop if we want to manage a group/team/community effectively.