(I thought that Ubuntu's upgrading (12.04 -> 16.04) lost a useful option, and I wanted to propose its returning.
Then I found that this option was vastly improved; but the answer is so generally useful that I propose to leave this question as general.)
Where should I place the suggestion? At the https://bugs.launchpad.net/unity? Thanks!
"Suggesting" changes can be a rather loaded term. Here's why:
Ubuntu has always been a contribution-ocracy. The folks who get developer attention are the (fellow) folks who contribute code.
Unity is now being maintained and supported by a few community volunteers.
Neither of those groups appreciate drive-by ideas much. They are already busy enough with projects that they care more about. Most are volunteers - they work on what they please. The professionals, of course, work on what their employer wants.
Successful community suggestions tend to have the following characteristics:
Wishlist bugs usually meet few of those criteria, so few are picked up by the (volunteer) developers.
Suggestion: Get to know the Ubuntu community contributors before pitching an idea. Join a team (testing, documentation, support, bug triage, upstream, whatever) that you find interesting and find a few ways to contribute. Observe how others make suggestions, and how the contributors and community responds, the communication channels they use, the resources they refer to. Time well spent.