1. isometric views; buttons where you can automatically view your object from the top,side or bottom.
2. object orgins; I propose that the build menu has an option to enable a 3d cursor. A 3d cursor determines the orgine of your object instead of you having to click inaccuratly to place it. It would also have a secondary grid system starting from your 3d cursor spawning out in all directions. On this grid system the 3d cursor would be 0,0,0 it would also be intergrated with the grid diagram when you move your objects.
3. lattices; a substitute for standard vertex modeling would be latices. These lattices would only have four vertices in a cube outline.
4. (a pet peeve of mine) customizable displacement of duplicates; you know how the X and Y add .5 meters to the original X and Y when you duplicate. I think being able to change the displace ment will just make building things faster.
5. custom buttons for custom shapes.
6. Sometimes when you have several shapes overlapping and you add a texture it gets all fuzzy in between, well how about an option to treat multiple shapes as one.
7. I think that the current build interface is perfectly suited for those who haven't used a 3d modeling program. I personally have trouble not being able to switch views with the keyboard. I suggest an alternative interface, or even a customizable interface, that you is like a new tab except instead of changing views (entirely) it adds a few windows and changes the keys.