Biggest problem is only that sony wants to protect their intellectual property and that they put some kind of "hardware abstraction layer" around the ps2 hardware which results in the fact that you cannot use any hardware directly, you can't even read a memory card in sony's format, you have to mount it and format it (which renders it useless for normal ps2 use) so this is imo a rather bad move by sony .....
(p.s. I read something about this in an article I saw the other day but now I have a some problems locating said article
)