Im not sure why they opted for a 2nd tier. They would have been fine with just a basic and a deluxe. Basic would be akin to the existing PS Now with streaming of PS3 games as well as streaming / downloading of PS2 and PS4 games. Those that offered online multiplayer would work fine without the need for + (as they do now).
The deluxe would take all of that and add in online multiplayer for retail games not in the service. PSP, PS1 & PS5 streaming / downloading as well as new game trials and cloud saves. It would have been pretty easy to have only two choices. The inclusion of a middle point that strips out the PS2/PS3 streaming/downloads and just makes it PS4/5 downloads only is pointless.
i guess one cool aspect that is kind of like GP is the new game trials. Sony may release day 1 trials for new releases and then you can choose to keep playing by paying the full game price to unlock that trial into the full game or go buy it at retail after your trial ends.