ok, so i didnt read all of your post, its pretty long but after reaching a certain poinn i realized what you were concerened about...

i must agree with you in some cases and disagree with others, first of all, "sims dont sell".. well, ofcourse they do sell but we all know that they can never sell as much as arcade games.. there's no competition there, you have to draw the line between realism and playability...

i too despise call of duty for their arcade like approach to war games, killing 200 men in a tv room? wtf? what were they thinking? the game should FEEL realistic but still be easy to play and you have to know what youre gonna make, if youre aiming for fast paced action then ofcourse you cant aim for too much realism...

i personally wont buy a game that is too sim like... sure you might say, oh well... am just one guy... but alot of gamers will the say the same, you have to kno how to draw the line... plus we cant help much here if we dont know what you had in mind when you said realism, how would you code a standard machine gun to behave then? it spreads alot without aiming and you get a tighter cone of fire when aiming down the site? or do you have something else in mind such as bullet drops, wind and all a that???

at the end of the day, you can either go full sim and risk releasing yet another game that doesnt sell great, argue this if you want but we all know that sims dont sell alot in comparison with arcade... all the major shooter titles out there are arcade like... you have to blend them to get what you want, so this thread should be aimed more about how to balance it and keep great gameplay.. i wouldnt buy a sim, i wouldnt even download it if its free, not trying to sounds harsh but i honestly dont have the time but i AM aware that there are ppl out there that like sims..

i also have couple ideas for war game but i prefer not to say what they are

i love game design threads like these.. hopefully i can help