Indoors combat was a forgotten aspect in Arma 2.
If the game could improve in how the game handles object physics and if it could randomly decorate buildings to not make everything look like empty shells it would feel even more realistic.
A buildling could be a snipers nest or a solid bunker if fortified with sandbags or traps, a really valuable asset to any fighting force trying to defend a position or simply hide from a superior force for as long as possible.
Arma seems to do open generic territories very well and it is very cool to walk around in a big world and not feel limited in how you approach a location.
Indoors, you do feel cramped and awkward because the controls and movement of the soldiers don't seem to fit well with the narrow spacing of a door or in between furniture. A click-to-cover or click-to-peek-around corner sounds like a good idea. Also a peek through window button would help a lot if you're using the building as a defensive structure.
How can Arma improve and become almost an FPS shooter in the way it handles firefights in-doors, I mean I want to feel the intensity and competitiveness of two parties fighting - and not have the outcome decided by a glitch or who could win by using the camera to get the right angle to spot someone sneaking around inside.