vespaz

1.) is actually a bug 2.) not my area, but physx vehicle setup might develop too.. the config file is enormous and one can spend days playing with parameters.. I look forward to what community modders come up with 3.) grenade extensions are still planned 4.) not my area

It has the most features - for example physx alone is full of possibilities. Plus if the Steam thing is done right, easier access to mods for broader audience - more motivation for modmakers.

Let me quote Joris: These early-access and test programs are really exciting for us. Particularly the ability to fully mod the Alpha is something quite unique in the current industry. Many of the games are even moving away from modding the final game. I can’t wait to see what our community comes up with before the full game is released. http://www.rockpapershotgun.com/2013/02/28/czech-out-bohemia-talk-arma-3-alpha/ In another article he mentioned the updated modding tools will just be released later, the reason being that they are not done yet. Which seems totally understandable to me. How can someone conclude from that Arma3 is moving away from modding, if BIS stated the exact opposite?

I think the exact opposite is true - Arma3 will be more moddable than all previous titles. It's just that full SDK is not yet prepared in time of the Alpha.