For the campaign:
- Add co-op. And not some separate mode like in Resistance 2 and Modern Warfare 2. Add it alongside the normal singleplayer experience. Killzone 2 felt like it was designed for co-op as is.
- Get rid of Rico and improve the cast in general. The Legion annoyed me in Killzone 2. They were a bunch of bullheaded, trigger happy, trash talking douchebags (save Garza... and now he's dead -_-) that felt more like a bunch of rookies looking for a fight rather than the most experienced group of soldiers in the entire ISA invasion force. I'd expect such a group to consist of characters like Aragorn from Lord of the Rings or the main character of Soldier. Mature, stoic individuals that lead men into battle through example, and aren't afraid to give a bit of advice here and there, rather than just bitch and pick a fight at the most inoportune time.
- Incorporate a deeper narrative, one that combines the improved cast from above with the imagery of Killzone 1/2 and heavily incorporates the backstory of the Killzone universe from Killzone.com. I want a story that better conveys the many nuances of the Helghast/ISA relationship, and sheds more light on the long history between the two forces. Killzone 2 had an incredibly weak story that did nothing more than take you from battle to battle. And sometimes it didn't even manage that - all I remember about the attack on the New Sun was that I was there and bullets were flying all around.
- Alongside a better narrative, toss in a few more impressive set pieces ala Uncharted 2 and Modern Warfare 2. Killzone 2 had its moments, but they were fairly few and far between, and I know people who missed some of the most impressive segments for stupid reasons like looking in the wrong direction. Guiding the player a bit more in these instances (turning around to see the ship crashing in Half-life 2), or making them so they're completely unavoidable (the collapsing building in Uncharted 2) would help strengthen the impact such scenes have, and would guarantee that all players are left wow'ed by such moments.
- While more set pieces are a must, don't rely *too* heavily on scripting. Killzone 2 had some great AI, and I'm sure Killzone 3 will only improve upon that. It's an advantage it has over the likes of Call of Duty, and they should still include plenty of large kill boxes in which to show it off.
- Include more enemy variety. Bring back the Helghast attack dogs from Killzone: Liberation!
- Make the Helghast rifle actually worth something again. In Killzone 1, that was the only rifle I used. In Killzone 2 the ISA rifle was improved a good bit, and it became an all-purpose weapon that made the Helghast rifle completely moot. Everyone uses the ISA rifle now, as the Helghast rifle leaves you at a significant disadvantage in multiplayer.
- Differentiate between the ISA and Helghast arsenals. In KZ2 the only unique weapons per side were the main battle rifles. Having unique sniper rifles, rocket launchers, etc. per team would be nice, even if the difference is merely superficial.
- Use the post-patch, high precision mode controls from Killzone 2 for both SP and MP. They're the best controls in Killzone 2, as they removed all latency while still providing a decent sense of weight and excellent accuracy. And yeah, some of us were fine with the pre-patch controls, but the fact is a lot of people couldn't get into them, and the fact that there are actually four control styles of KZ2 floating around in the wild (pre-patch - some people don't have internet! - and post-patch controls for both SP and MP) have only hurt the game even worse. Imagine a person with no internet buying the game based on what they played at a friend's house who had internet. They'd be getting a totally different package. Having a consistant set of controls from the getgo is a must, and using the one that the most people like (while still retaining the feel GG was aiming for!) will help the game to garner the commercial success the second struggled to achieve.
For mutliplayer:
- Change the default game types. In Killzone 2, the majority of people just create a round of Warzone, which is a chaotic mess as it's 32 players even on the smallest maps. They should have included two types of Warzone for you to choose from: Small Warzone and Large Warzone, the former of which would be 16 players from Corinth Crossing up to Radec Academy or Visari Hammer, and the latter of which would be 32 players from Pyrrhus Rise down to the Visara Hammer. Maybe toss in a mid-tiered mode too, with 24 players on Tharsis Depot through Helghan Industries. I got tired of hopping on the Killzone servers and finding only Warzone available to play. 32 players on Blood Gracht is not fun! As a result, I always made my own games, but unless I could get 3-4 friends to join immediately, the game would never fill up. Especially when playing in the middle of the night.
- Bring back Visari Hammer! That has to be the most beautiful level I have ever played.
- Other than that, just improve upon stuff in general. Not sure what they could do in the way of classes, but maybe they could add a second secondary badge or a tertiary badge to each class or something. And I wouldn't mind seeing a few new round types. I honestly thought multiplayer was excellent as is, but I trust them to come up with some good ideas for the next game. I love objective based mutliplayer!
The art of Killzone was what initially drew me to the series, and the multiplayer of Killzone 2 turned it into my favorite FPS franchise. I will be hyping Killzone 3 from day one. :D
Edit:
And screw vehicles in multiplayer. That would totally break the current style of gameplay they have going. Maybe if they made compeltely separate maps and round types dedicated expressly to vehicles it would work, but then they'd be forced to take focus away from the multiplayer mode they have already worked so hard to construct.