I've seen many people over the years complaining in servers that "RS sucks compared to RO2 vanilla" but when I ask why, I never get a straight answer. Which naturally isn't too useful when we're trying to work out which things to change for a sequel!
I have not played R01, but I have played 1500 hours of RO2. I can confirm firsthand that most players--both casual and hardcore--tend to prefer vanilla RO2 over rising storm, myself included. I will do my best to explain.
Map Design
From personal experience, the maps many RO2 players like the best tend to be (disclaimer, everyone has personal preferences) Spartanovka, Mamaev Kurgan, Barracks, & Red October Factory. I pick these simply from my observations from playing campaign mode a lot and listening to chat in-game. These maps (outside of imbalanced apartments for the attackers) tend to be voted for the most even when factoring in attacker difficulty.
These maps have several common elements that I've noticed are important to enjoyability:
1). First they are what I would call semi-open maps. Large swaths of the map are open ground and thus instant death without smoke. Other areas are close quarters "strongpoints" and tend to have enemies clustered within.
2). The capzones are relatively close to each other. For example, cap C and D are 1 street away from each other on barracks. On Spartanovka, each cap is literally 5 or 10 feet from the next and so forth. On more open maps, the distance between caps is somewhat greater but the caps are well within firing view of each other.
3). On these maps tickets are
usually the constraining factor, and time is secondary but still matters; attackers can get stuck on a cap for some time as long as its not
too long
What do these elements create? These maps are a brutal tug-of-war. By a brutal tug-of-war, I mean every inch of ground is precious. 100 lives (tickets) spent just to cross a single street in Stalingrad. 65 tickets to just advance 25 feet to the next housing block in Spartanovka. 85 lives lost to make it to the next nearby row of trenches on Mamaev. RO2's gore, character screams, and partially functioning death moans only add to this atmosphere so well. This is the gameplay I and many RO2 players know, love, and remember.
Now to contrast with other maps, on Hanto, when trenches are capped, the fight moves very far back. Same with B cap. The fight moves 200 meters away once capped. Theres an artificial feeling to it as if each capzone is its own seperate ecosystem disjointly related. The same goes with Saipan. Once a zone is capped, the combat zone moves very far back. What I specifically mean is, the buildings in previous objective that was capped is not in danger from enemy fire. The fight is completely moved to a separate area and not just continued. I truly think people would prefer it if every inch had to be contested with a cap-zone across every parallel street.
Now on the topic of semi-open maps, Rising Storm maps have a lack of long range fighting. Most fights tend to be close range because there are bushes, dips in the terrain everywhere. It leads to gameplay feeling the same with constant "gladiatorial fights" up front and close. The lack of automatic weapons for the Japanese and fast moving flamethrower guys only adds to the aggravation. If you notice, the most popular Rising Storm map is Iwo Jima which has a good mix of open versus close range combat and somewhat closer capzones. What I fear is that the devs have shied away from open maps thinking new players won't like them. Yes, there are maps that are TOO open. These are ARAD2 and Barashka. A lot of players strongly dislike these maps. There is 0 cover almost everywhere. But remember there is a sense of accomplishment to overcoming challenges and it feels good when after a hard fight you managed to cross the street/field of death into the next building. Winterwald and Bridges are popular because of this as well.
Now let me end by saying what a good RS2 map should be like if it were designed along the lines of a successful vanilla RO2 map.
Good small map: 2 giant rice paddies. Your cover consists of 2 dike walls, a single burned out APC, and 2 bison carcasses, nothing else except a few bushes along the edge of the map. Squad leaders must use smoke to leapfrog. Next cap: another 2 adjacent rice paddies 15 feet away; the fighting doesn't just stop, it keeps going. Next cap: an open dirt road just beyond the rice paddies. A single ruined building to the right side is a good stepping stone to cross. Getting from the ditch on your side of the road to the ditch on the other side is fraught with danger. Final cap: past some bushes and trees but nearby is a group of huts. Once the offensive team manages to get a foothold, a 16 man rush win the game.
Such a map doesn't hold players hands with cover everywhere. It forces players to think hard about where to go and how to attack. It offers a good mix of long range combat and short range combat to suit multiple playstyles. Its memorable because the map forces you to fight hard to advance just a little bit.
Thats my 2 cents. P.S. flamethrower run speed could be toned down as well.
I hope others see and understand what I'm trying to say.