I think this would be better for everybody involved. I don't think it really messes with the minimalistic style this app is going for because you can just choose not to have it, but having it would definitely speed up the workflow of many people including me. Removing the limit entirely would be a good move, or be able to add folders for the shortcuts to be able to organize the frequently visited websites better, just like how bookmarks work.
It's possible to add more rows of shortcuts. I've done it before by following instructions I found with a Google search. I cannot find the same advice now. It's really simple. Go to config and change a 4 to a higher number. I just cannot remember the line in config that requires the change.
Type about:config into your address bar and hit enter.
This will take you to a Warning page. Click the box that says "Accept the Risk and Continue".
The next page has another warning. There is a search box there, put the following in that box. "browser.newtabpage.activity-stream.topSitesRows" without the quotation marks.
Or, you can click "show All". That will take you to a very long list. It's alphabetized so you can easily scroll it down to, "browser.newtabpage.activity-stream.topSitesRows" You will see the numeral "4" right there. Over to the right side there is a "pencil" icon. Click on that to edit. Delete the "4" and replace it with the number you want. The pencil icon will change into a check mark icon. Click on that and you are done. I have tried "6" and I have tried "8". Both of those work.
Justine, a Firefox Product Manager, is hosting a discussion thread here on Mozilla Connect asking for feedback to improve the Firefox new tab / homepage. And you're all invited (of course) - check it out and add your thoughts via this link: Share Your Thoughts on the Home / "New Tab" Page! 🖥️ [thread 2]
It's a great opportunity to share ideas and communicate directly with the team working on this feature.