Why can´t the install be optional. like the first time the game is run it asks "do you want to install a portion of the game to the harddrive? This will speed up loading times." and then if one answers no the game continues.
Then they could have the install option in xmb too, so one can install it at anytime. They could also have the option to install the whole game or just the most nessecary parts. I know BD-discs can be 50GB but all games doesn´t use that amount of space.
Another nice feature would be to install to a network drive. Then people with small playstation hdd and lots of games can have as many games they want on their computer since 3,5" drives are so cheap these days.