Because of recent changes to Firefox's autofill behaviour, I asked the team to consider adding the "remove suggestion" button beside awesomebar results, but after more thought, I'm not sure that's clearly a good decision. Adding the "remove suggestion" button is actually quite risky! I'll explain: when I use Chrome, sometimes because of my lack of patience and wanting the browser to just give me the autofill result I want right away, I will click the "remove suggestion" button (without putting much thought into the consequences of this). In the very short term, I'm happy, but I later regret it once I realize that, for example, that twitter account I go to once a day is no longer autofilling at all because I clicked the "remove suggestion" button earlier that day! I feel confident in saying that, for many users, the addition of the "remove suggestion" button may have actually resulted in more harm than good and we should not make the same mistake Chrome did. Even for people studying UI/UX like myself, misusing the button is too easy and too tempting. I believe only offering the "remove suggestion" button is a flawed decision.

The better and much less risky solution to this problem would be a downvote button! (whether you implement a downvote button instead of the "remove suggestion" button or both buttons, I don't know) I understand that it's important we not confuse or overwhelm users, but in 2022, normal, casual users are familiar with the downvote button. Of course reddit has them, but now even twitter has a downvote button for replies. I've also seen downvote buttons in the "Google Discover" feed and I'm sure there are many other examples of the downvote button appearing in popular websites and apps. I think this would be a great and meaningful improvement to Firefox's awesomebar experience, and it is far less risky than the "remove suggestion" button Chrome implemented.

We are already evaluating a menu per result that will also include the possibility to dismiss results more easily, with the scope of giving users more control over their result composition.
The reason for which we don't plan to just provide a simple button, is that the results can have many different sources, for a bookmark for example one may or may not want to remove the bookmark. For an history entry one may just want to remove that url, or the whole site. Similarly Top Sites may include different options.
And as you correctly said, it's too easy to misclick a simple removal button.
Thus, I'll just dupe this to bug 1041761 that is our tracking bug for the future improvement. and more info will come in the next weeks/months.

Thank you! Though I just want to point out, I didn't see any mention of a downvote/downrank option in that bug. A downvote function is not the same as remove/delete/hide