Yes forgot about Vietcong. Another little gem there. But more a realistic FPS than tactical game. Still...ya good times.
I think to much focus has gone into lots of guns. Here is what I mean. Just how different from an M16/m4 is an FNC, G33, g41, G36, ak 74, ak100 series, famas, scar whatever, or name your 5.56/5.45 gun here. The answer is not much. If you take Hidden and Dangerous 2 (or 1) or Vietcong they both had a decent selection of arms, but ended up pretty balanced in a game sense. Made the actual gun play pretty interesting. It was generally more than spray and pray. In Arma series this is totally possible. Arma 3 when I was playing a lot of KOTH was a heck of alot of spray. And it worked a bit to well. So I say has to focus on good historical and realistic gun play that also needs to be game balanced. Here is where a PVP game like RO2 sort of went mildly off the rails. The gun play with rifles is pretty groovy. A lot right there IMO. But its mangled with SMG's everywhere that are a bit TOO good and things like MG34 with 100 round belts and the like. With few real penalties to using it. H&D 2 did not fall into that hole and focused on the Bren gun and cz26 ( well the German version that they adopted). In MP good call. In single, well blaaa. And the SMG's where not the kill all gun either.
So having a good selection of guns, good. Huge selection of guns takes away time and money from other stuff. OFP had alot of guns. But was limited to ak74 variants and m16's at first. With of course m60's and pk's. Which where damned dangerous but kind of hard to run and gun with those.
Need a good enemy and friendly ai. Arma 2's system of pick up your buddy or have the ai pick you up I thought was a good game land balance thing. Why arma 3 dropped that, I find odd. A lot the games like H&D 2 and vietcong where not true free roaming games. But you had some choices. Sometimes a lot of choices on how to mount an attack. Helps the AI. I have never seen any ai in any game that handles open world 360 degree security all that well. Although the Stalker series (no, not quite tactical but sure fun) did a decent job. Although there still the player was generally forced to go into funneled areas where the AI ended up with help from the land form.
I personally find 4 or so man teams the easiest to manage in a true tactical game. More is not so great. But can work perhaps with a good ai with minimal baby sitting. Maybe broken down to a couple fire teams in a squad. So having good management tools for SP with an ai that is not stupid or suicidal. Arma at times is both those and can also be quite good. But you never know. I think this is due to the true 360 degree danger from anywhere. And really LARGE maps. Which is good and bad. Arma series its run to the highest point and shoot ai out of their range way WAY to much. Why on earth are the enemy ai in arma always in freaking open fields with dead ground everywhere. LOL.
Just some thoughts there.
But it seems that 180 degree freedom of action seems to be a better experience than 360 in a huge open world from my experience. Well when AI are involved.
OH and I would love to see the return of morphing terrain. The ability for explosives to dig shell craters and players and ai to dig basic things like shallow fox wholes real time. Also some decent well modeled realistic vehicles. Not things like main battle tanks so much. More like APC's, half tracks, armored cars, jeeps, land rovers, maybe a well balanced light tank with low velocity guns (like m24 or scorpion recce vehicle). And where vehicles with a plow could dig themselves in a bit. More real world vehicles that things like Steal Beasts or say Kharkov 1942 does. Where a human driver can freaking stall the vehicle. Where a manual gear shift gives the player something to do while driving as an option. But not these incredibly unrealistic vehicles like arma series does. You know, game studios, hire, consult, or go find someone with a private owned tank/apc and drive the bloody thing to see how wrong those are.