The idea that big maps are the solution to all our problems is a fallacy.
I could mention no shortage of old tactical shooters that were running on engines incapable of making large outdoor maps, whose largest maps would make Appartments seem huge by comparison, and that didn't stop them, it did not make the gameplay regress into run and gun or pop-out snipers (and most of thease were modern shooters too, SMG's and AR's for almost everyone, semi-auto snipers and shotguns fro the rest).
Yes it is easier to encourage tactical play on an open map than it is in a tight urban map, this is true, but a good tactical shooter should have no problem doing both, it all comes down to the game's mechanics, if they properly reflect human limitations, then people have to adopt realistic playstyles to play them, and in a good Tac shooter this happens naturally for the same reasons it does in the real world, it's what works.
But Ro2 is no Tac shooter, and that's the problem, it comes very clouse to beeing one, we can point to features it has that are superbly realistic, but on the whole it drops the ball and lacks the conviction to go the distance, and doesen't take the critical final step to make them realistic enough to work, or for gamey alternatives to not work.
Bigger and more open maps will not solve this, all it will do is take the game from arcady gun and gun CQB furballs, to equally arcady snipeout camping fests, the underlying game mechanics must be solved before we'll get anywhere.
In truth there is nothing horribly wrong with the HoS maps, some balance problems, a few spawns would work better if moved a bit, things of that nature, but thouse could be fixed, and if the game mechanics were up to the task they would not be a problem. But they are, and it's not the maps fault, they could play as well as Odessa, Kessel or Leningrad if it weren't for bigger underlying issues with the game mechanics.
And the funny thing is, it's actually fairly small tweaks that are needed to get the game to where it needs to go, HoS has all the needed mechanics in place, they just aren't configured right for a Tac shooter.
But technically, we could say the same for the CoD games..
We're something like 90% there, the game just needs to take thouse crucial final steps to reach it's destination.