The NEW arch system, whether intended as a priority or not, allows for and promotes building without having to dig or work with dirt at all. This was one of the reasons so many people gave up on trying to build --the manipulation of dirt was too difficult for them. Under the NEW system, if you choose not to work with building up dirt levels, 40m is the present limit. To keep with this improvement trend --allowing more players the ability to build multi-level structures without having to change any dirt levels (which among other things looks much better) --the vertical limit in my opinion should be increased to the thus far only teased 60m limit.