There is no substantial evidence of what direction the trophy system is evolving to and all the rumours so far have been unsubstantiated. I'll offer my insights into what
I think Sony should do though: The PS Vita was released allowing users to transmit trophy data between the PS3 and Vita but only because the Vita was like a PS3 extension, except portable. Sony should not allow trophy transfers to the PS4 just so people that are new to the console can have a fair headstart in the trophy leaderboards (An example of this being PSNProfiles where some members compete to get higher points.), racing or rivalling their friends in trophy count.
Trophies/achievements aren't going to be there forever and let's face it: We're soon forget about them once the images are gone from our mind. We don't collect trophies to always stare at a virtual icon, we collect them for bragging rights, rivalling our friends, bang for the buck, or out of pure boredom. It doesn't matter if those trophies you've achieved are lost, what really matters is the memories you have of achieving them.