RO1 had a certain level of what Clausewitz would call "friction" imposed onto it, so that every action was kind of delayed and sluggish, and felt gross, as any action taken under fire would be impaired by nerves, adrenaline, confusion, lack of information, etc.. And since every player suffered this equally, it meant that you wouldn't as often see players rush across open ground fully knowing an enemy MG was covering it since they couldn't cover the ground fast enough, or trying to sweep a whole house by themselves with an SMG because they knew the would either walk too slow with sights up, or be too inaccurate with sights down, and raising and lowering sights was too slow to do on the fly. Players were forced to work together and behave cohesively as units because they were rubbish on their own. In RO2, every action is faster, smoother and more gratifying to perform, so players are more bold, more effective alone, and less patient with one another in coordination. However since both teams have the same freedom of movement, you have a minority of truly skilled players dominating, and then a majority of mediocre players who start to coordinate by necessity and the whole system starts to equalize itself... if the dominators haven't already won the match with their prowess by then. The window for that transition to take place seems shorter in RO2, and this frustrates the older veterans who struggle to recreate the old games they remember having (often on the very same maps).
Of course naturally any veteran could perform superhuman Audie Murphy feats when they needed to back in Ostfront, because they naturally developed an intuition for what could and couldn't be accomplished at any given spot of the map in any given scenario, just as in any FPS with a fixed number of maps, weapons etc., but a rambo would often clear a house by himself and then fall back onto the support of his comrades, not push on to capture three objectives and blow up a tank. And when you pulled off a stunt, it felt like a greater accomplishment for all the bull**** you overcame.
RO2 and Rising Storm reduce (but do not remove completely) that friction, because when you focus on it and are conscious of it, it is not fun at all. It's only tolerable as an ingredient in a greater experience, a subtle nuance that compels you towards certain bahaviour. If you watch the reloading animations in RO1 when the player is not crawling on his stomach under fire but is simply standing in an empty street on an empty server, he looks slightly out of practice, maybe even incompetent and a bit silly, whereas RO2's animations may be too fast for frantic battlefield action, but are so simple and utilitarian that you wouldn't really scrutinize it at all on an empty server. The new design philosophy is to get out of the player's way and let him fight the battle, rather than make him fight the controls. Sometimes it's an improvement and rewards quick thinking and reactive tactics, not to mention give players on the flank or in ambush the feeling that they're calm and collected, but sometimes it opens the floodgates for abuse and "gamey" behaviour. I've gotten used to the new mechanics, and manage to find myself having fun both on a tactile level (RO2's general gunplay is superb and makes killing very satisfying) and a cerebral level (outsmarting the enemy when he becomes set in his ways). And yet I still frequently die "unfairly" just as often as I used to do in Combined Arms for UT and Ostfront thereafter because the easier mechanics are still punishing when you get too cocky and try to be a dip**** (which I often do and have always done... after all, my primary complaint when they first added movement inertia was that it made bayoneting people harder, at a time when most players never fixed their bayonets as a rule). I actually have trouble enjoying Classic mode now that I'm acclimated to the new system. The very mechanics that made me fall in love with the IP feel arbitrary and obtrusive now.
Now, the suppression system is supposed to bridge the gap so that all your Quake 3 Arena super-skills turn to **** as soon as a supersonic crack sounds over your head, but rather than slow you down in subtle and immersive ways, it apparently makes your eyes water and gives you hysterical colour blindness instead. It's an abstraction like everything else, but I'll agree that it's poorly implemented. On the other hand, I find it less irritating than Darkest Hour's version which gave your avatar a full epileptic fit for every individual bullet that flew within a five foot radius of his body.
I'm reminded of a Half-Life 2 mod called Plan of Attack, which tried to force firefights to last longer and allow for tactical coordination by imposing wildly inaccurate conefire and low bullet damage. The small maps could play out like a tabletop turn-based tactics game, but in an FPS, and it was very jarring. That mod had a very overt and obstructive design philosophy with the best of intentions, but it was not fun to play because nothing felt convincing on a tactile level, the fidelity of the graphics and fluidity of the character movement implied something that the shooting mechanics did not deliver. RO1 bridged that gap better, RO2 seeks to tighten the gap even further.
Now, even if the general RO2 mechanics are preserved in RS2 or tweaked further, we really can't say how it will play because so much depends on map layouts, and the behaviour of weapons and how classes are balanced. RS2, if it seeks to simulate the weapons of the Vietnam war properly, will inevitably feel very distinct from RO2 and RS1. We already know from RS1 that Anti-Matter Games aren't afraid of taking risks with asymmetrical balance like unique weapons and mechanics for each faction to encourage historical behaviour, so I think RS2 will see less "commercial" compromises made than if Tripwire was fully developing it. But again, we really don't know yet.