Barrier: it won't be possible for non-owners to do terrain modifications, create or remove energy streams and paint (there will be some additional features coming in 0.8 - we're still discussing how should it work with vehicles and ships)
Larger doors: not sure yet, but it's very likely
In general, you will be seeing only a few new blocks being added to the game within the couple of next updates - not because we wouldn't be working on some (actually quite on the contrary - some great looking stuff is being created ) but because those blocks will be released with the update featuring the new world 
    • Thanks