Most of those points are good ones, theres a lot of un-tapped ideas the XMB could be using. The in-game invites one isn't really valid tho, its a game specific thing, it's up to the developers to utilize that function.
I'd like to see more integration with psp, like an AVC video encoder on the XMB for compressing the videos that are on the ps3 to make them compatible with psp.
An audio converter, you can rip from a CD to mp3, aac or atrac, why not offer those conversion features on the XMB for tracks that are already on the XMB.
External audio file playback during video play back, being able to use one of the audio files during video play back, usefull when you have multiple languages for the video, or if you have a directors coments version
Those are all ideas that present no risk to sony in terms of security, they are already implemented in some way or another (like the audio conversion)
I think sony should also get rid of the auto pause of video when you use the XMB, i watch stuff alot on my ps3, and when i get messages (or use the chat feature) the video pauses. Very anoying, i don't know any one that likes it. Especialy anoying if i have music videos on. An option in the XMB wouldn't hurt any one
Voice chat should be made so that the user can use other system fetures at the same time (such as gaming)
Oh! for gods sake they need to stop turning the music off every time i wana do something, jesus! my mobile phone can play music while i change it's settings, why cant a ps3??
PlayTV, awsome for recording your fave shows, sucks at giving you access to that content. PlayTV can only be accessed while you have the playTV reciever plugged in, if you take ure ps3 to a friends, you cant access the videos in your library unless you take the reciever. Anoying. PlayTV does allow you to transfer your videos to the XMB, only to have the XMB not able to play back the subtitles (it's sonys own hardware, talk about bad intergration) How about having the recorded videos listed in both the playtv library, and the XMB?
Some other ideas i had that are more "funsie" and less "should be" would be, using the PSEye to control the XMB (like that mad movie with tom criuz).
Using the PSEye or other audio input, voice controling the XMB, so like "Friends" - "message box" - "down" - "open" or something, would be cool.
Moving backgrounds, like a gif image, video file, or even a specificly rendered background, like a picture of a waterfall with moving water, moving plants. Or a picture of sky, with moving clouds (i think theres something like that for windows PCs)
Got quite a few ideas in mind but those would be the ones that pop into mind just now