Eh, I'm divided on this as I feel like Killzone has had its time to shine and after 4+ instalments it never really struck gold (disclaimer: 1 was crap even for its time, 2 was good but with caveats, 3 played better but was overall worse than 2, Mercenary was genuinely great but scuppered by the hardware, I didn't play Liberation and Shadowfall was like 1/3 an excellent game but then level design and story went down the toilet).
So I kind of hope that the second team at Guerrilla (led by Simon Larouche) are working on a new IP, because I think modern Sony looks forward rather than back and wants its development teams to have big hits with new IPs, like Horizon and Ghost of Tsushima. That being said, I would buy the shit out of a Killzone Collection on PS4/PS5 and I wouldn't mind if their next game was a Killzone reboot, this time hopefully with better characters and storytelling.
There's a very strong chance they're addressing that though. Quoting a post on Sony's potential incoming FPSs that
I made a few months ago, of course based on the assumption that these games will all be FPSs. I think there have been some rumours recently that the Guerrilla game might be a Horizon TPS co-op multiplayer game, which honestly doesn't interest me nearly as much as a new FPS IP:
"I've been thinking about it recently and I think there's a good chance Sony will have 4 major FPS launches in the next ~4 years. As a fan of the genre I really hope they bring the usual PS Studios level of polish, hopefully some good storytelling and some unique art and settings. I would like to see some sci-fi and really creative stuff in their games, although hopefully there's a good variety of styles and settings. I'm not really a fan of contemporary war settings so I hope the games are a bit more interesting than that.
- Guerrilla's second project – I feel like this could easily be MP only, or if we're lucky it will have a campaign component too. As a predominantly offline player, I'm hoping for the latter, obviously. While I enjoyed most of the Killzone games they would need to step it up a gear with much better writing, characterisation and a higher quality of level design. I also think there's a slim chance that the Bungie Netherlands studio collaborates on this, so Bungie's first production under PlayStation would be a Bungie x Guerrilla crossover, which would be exciting to see! I think this will be the first to release out of the four, with possibly a reveal this year but probably a reveal next year, for a release early 2024. I expect most of the Horizon development team will now move over to this project, probably with some held back for Horizon DLC and then a small number moving on to Horizon 3 pre-production. I think it's likely this will be a new IP and unrelated to Killzone.
- Deviation Games' new IP – they were at ~110 staff when this was revealed mid-2021 so I assume it is already in full production, although they're likely to keep staffing up for a good while yet. I don't really follow COD (the last one I played was Infinite Warfare) but you can't deny they feel good to play and the two heads of this studio were IIRC the creative director and executive producer on the Black Ops series, so they have some pedigree. I imagine Sony will market this heavily as a major release and they will very likely have acquisition discussions with Deviation. I'm really hopeful this will have the whole shebang with campaign and multiplayer (and possibly a COD Zombies-like component too, as that seems to have been a major success for the Treyarch games), and it wouldn't surprise me if it has a similar gamefeel to COD, although personally I am not a fan of ADS or the very fast TTK in that series. I'm expecting this to be ready for release in late 2024 or early 2025, and IIRC they have been partnered with PlayStation since 2019.
- Firewalk's new IP – I think the question of what happens with Firewalk is an interesting one now that Sony has acquired Bungie. Honestly I would love them to just create a focused single-player FPS with the wonderful momentum and feel that Bungie's FPSs have, but I think they've already talked about blending SP and MP design which makes me think of Titanfall 1, and I don't find that very appealing. However, hopefully they will go in a different direction from Bungie, Destiny and Halo so they have something which is visually and creatively distinct. I looked them up a month or two back and they were only about 60-something staff, so I expect this game to be a good 3+ years from release.
- Bungie's next game – and lastly we have Bungie, undoubtedly the crown jewel in Sony's FPS output. I wouldn't like to speculate what kind of game they are working on next, although after playing Destiny 1 I would hope they have a clear divide between campaign and multiplayer because the campaign in that game didn't really work for me. I wouldn't be surprised if it's another live service game as Sony will want to recoup their investment and they can probably have a smoother launch with a lot of lessons learned from Destiny, although personally I would be really disinterested in that. Halo and Halo Reach are two of my favourite FPSs ever, so I'm excited to see them launch another new IP, even if Destiny didn't fully land for me (and I haven't played Destiny 2 at all). Whatever they do next I hope the worldbuilding and writing is better than Destiny. I'm expecting this is a long way from release and we're probably looking at late 2025 at the soonest, although Sony might reveal it early to create hype.
Elsewhere I think there's a chance one of Santa Monica Studios or Naughty Dog make an FPS next (I think I'm just basing this on hope rather than any evidence or hints), and we will probably see a sequel to Farpoint on PSVR2, and possibly Firewall: Zero Hour (I get the impression this game is good but it didn't do very well). As a big fan of the genre I'm looking forward to seeing some big AAA PS-backed new entries over the next few years."