I don't know how many times already I've had to remove this, and now nothing seems to work anymore. Setting browser.newtabpage.activity-stream.newtabLayouts.variant-b to false should work, I guess, but it doesn't.
Edit: shishka_b0b has posted a solution (as for enlarging the quick link icons, I forgot the simplest solution - zooming in the page)
Some alternative options: there are many many new tab page extensions you could try for a different look/layout, or you could put together your own basic html page of shortcuts and set it as your new tab page.
I tried out one of the extensions (Tabliss) the last time they forefully changed the new tab orgnisation, and it seemed pretty good, but it loaded somewhat slower than the built-in new tab, so I'd really prefer to just modify the default new tab instead of switching...
Maybe I could try making my own html and see how that works.