It's warfare, military simulation. It is a unique product which has not any rivals. There is a plenty of warfare games: COD, MOH, BF (except the case when you run Project Reality mod on BF2 base) and many more, but there is no simulation, simply. Correct me if I am wrong, but it's the way it's. Also none warfare game can boast itself havin' a bloody hell huge maps, a variety of guns, vehicles.
Warfare games are actually developed to have SP, a story line... It was always. Nowadays the developers are more prone to create them to be good at MP, but it's just another CS, run and kill... No art in it. I would recommend them to get back on makin strong SP that for what those warfare were always awesome in the past. A long storyline was a key for previous MOH, COD titles, like MOH Frontline, COD the first titles. Nowadays they make useless SP orientating on MP which is even more useless.
Meanwhile Bohemia Interactive with its Arma title are orientated on MP stuff and providing a full warfare simulation experience. That has no any match at the moment. That what makes them the very special ones.