Hello VirtuallyMe. When a townie walks up to my mayor saying how lovely it would be if the town had a certain Town Upgrade again (different than a favor request, so there's no icon over their head), I usually take a screenshot of the suggestion, in case I get sidetracked and may not remember later what it was that they suggested.

If it's something you'd really like to see added to the game then you should really post your suggestion in the Virtual Town Suggestions thread in the Developer Feedback Forum (sorry to sound like a broken record). Otherwise it's likely to get buried in the current thread.