Frankly, the onlything I think they'd need to fix on the PS3 is three things.
1) The air intake: My PS3 gets so hot, I can hear the plastic form on the outside clicking because its expanding from the heat. And more than once I've had it freeze up on me because it got too hot, at which point it automatically shuts itself down. This is definitely something they need to look into.
2) HDD speed: Reading from the disk to the HDD takes quite a while. Installing games can take up to 2 hours...I can understand its uploading multiple gigs but that's a slower rate of data transfer than what my External HDD gets copying from a DVD. And even then, I can accept this. But loading times IN game are atrocious, mostly due to the read time on the BD.
3) Online support: I'm fine with the content of online and I really like the Trophies and Leader Boards for most games. However, downloading from PSN is quite slow. I doubt there's much they could do hardware wise to fix this. But they should still look into figuring out how to improve this problem.