i was LTTP but sly wasn't that great of a franchise. i think the franchise is special enough to the fans that sony should port them to ps4/5 but i wouldn't greenlight a new game in the franchise. i wouldn't buy a new one either.
i was day(ish) 1 for all of infamous. i mostly have the same feeling,.. a port of the ps3 games would trigger a rebuy from me probably but i don't really want another game in the franchise. i'd buy it if they did but i like new franchises that aren't tethered by legacy expectations. i think SP could do more by reusing the ideas but building out differently like they did with GoT.
the willingness to kill a successful franchise and start something new is one of the biggest reasons i love sony. sometimes a franchise is just played out where there is no where else to take it story or gameplay wise. sometimes its best to just "go out on top" so people always have good memories instead of milking it to death.
killzone is another great example of my attitude here. port KZ2 pleeeaaaassseeeee. ...but don't revisit it.