These games did get a lot of stick back then for not being Cod/Halo/Gears and we've had multiple entries of each and even a PS4 Killzone game that fell flat. Tired IPs that never really caught the imagination, I don't think they should try to inject new life into these well worn games.
IGN are on the right track for the first time in its history though, Sony should look at a new flagship FPS IP, try to make something gritty of higher quality. they have the teams and standing/sales from other games and should try to maximize a strong position.
Really they should already be doing it, perhaps they are and it's still to be announced as games take a long time now. Saying we hear you today and they release something 2030 isn't good. I hope AI can really advance so we can get bigger scope games in 2-3 years.
Can't speak for Resistance, but Killzone's precise problem was when the multiplayer was malformed into shit to chase the COD crowd.
KZ2 - 1.5x XP multiplier for winning. 0 XP multiplier for losing. Guess what people did in Warzone. They tried to win every time, and it was fun as hell.
KZ3 - 1.5x XP multiplier for winning.
1.375x XP multiplier for losing.. I'll give you one guess what most people stopped attempting to accomplish.
Similar story for Halo, Battlefield, and most anything else that isn't a single elimination per round objective shooter (CS, Siege, etc).
I'll give Epic credit - they invented a way for people to ignore the primary goal of killing opponents and instead reward people for dancing on giant toilets. Never saw that one coming.
An amalgamation of Killzone multiplayer games that strictly follows KZ2's structure would be great. We are obviously not getting any more Enemy Territory games, or a universe where people capture flags in domination modes in mainstream shooters, so this is the best to hope for at the moment.