From the screens it looks no different to ArmA2, that could just be teaser stuff, but unlikely. To be honest with you I can't really care for the content, any arma veteran knows most things that are played in any half decent community are from the modding community.
I don't care if it's future weapons and vehicles, someone will already bring in the older weapons.
But I do look forward to what they do to gameplay/ai/vehicle and player movement/interaction. Although it hasn't changed much in 10 years it still feels samey. Which is good because it promotes a slower/tactical gameplay instead of running and gunning.