This idea basically is the same as what we have now, except that we have pop ups instead. But many browsers think that pop ups are advertisements, and prevent them from opening. I think it would scare new users away.
Another thing is that it would very likely slow Armorgames down, as then it would have to load a lot of pop ups at the same time, which will slow down Armorgames even more. And speed is essential, right?
How would this make AG any better. THe only upside is that it would mean I don;t have to scroll all the way down to the 6000 odd point mark when I have unlocked new armatars. Which to be honest isn't that much hassle.
As the other said: Not something we need. There are so many other things we would rather have than this, especially because it seem rather needless (fn + down arrow or PgDn).