There is no real roadmap, since we simply cannot give an ETA on these features It will take a little bit more time until water is ready, for 3rd person we first need to rework our current character model (which may take a few months). Vehicles are only planned at a later stage of the game.
Btw. there would be no reason for moving to another language
I like the way things are going so far. Right now what sets this apart form so many other games is that there are not hoards of monsters waiting to mow you down if you turn around . You do not have to run around with a weapon in 1 hand. There are at least a dozen other games like that out there. I suggested Unity because it is free (just like your current engine) also I feel it will deliver a much better landscape. Voxel farm just released their engine and its landscapes are incredible.
I do not want to see this game turn into a farm fest(here we have to spend hours and hours gathering, or wait we got to eat or sleep ) That is why I believe in the switch system. If you want it , turn it on , if not turn it off. It then becomes a play your way. (I like what they did with skyrim and the entire morrowind system ) if you don't want something, turn it off. Using a switch system, you just turn off the attacks on unfriendly animals. People running servers could then set them up any way they want to. some people just want to build, others want to hack and slash. (IE 7 days to die style ). These are just my opinions.