A bit soon to tell for certain. There could be some issues with software currently in use handling the change over during burning. Will need to wait until someone has had a chance to actually try it. Not a whole lot of DVD-9 PS2 games out there. As for movies, the same issues could come up as well. You might want to keep an eye on what is going on at the DVDDecrypter site and others like it. I am sure it will get tested and tweaked by them more intensely then with the retail packages--especially with all the copyright legal wrangling going on these days.
If it ain't broke don't try to fix it! But, hell if you can tweak that bastard just a little bit more....hehehe.