EDIT: Actually, did the 1.61 enable running the browser and games at the same time? Because I had Uncharted open when I started the browser.
The multitasking between web browser and game already works to a certain extent. The restriction is artificially enforced. e.g., You can launch the web browser from *some* apps while a game is active.
Someone tweeted Shuhei to confirm:
http://www.neogaf.com/forum/showpost.php?p=35445389&postcount=9464