They should add hovering foundations to be able to build in the sky since we can already build on land and sea, why not in the air ;D
Also on single player they should increase the radius or take off how people that join your world have to be so close to you to play, what if I just want 4 or 6 ppl in my world to play with I don't want them around me all the time let them explore the world I create. I know I can make a dedicated server but I rather play single player with 4-6 people that could join my world without strings attached. ;D