An exponential increase to the current maximum size of the artboards. Programs like Autocad you can design as large as your computer can handle. In Illustrator, the current max artboard size is 227 x 227". I (and many others) would like to see this limitation increased to infinity, or at very least 20x it's current capacity. This will allow many who use illustrator to setup files for large format printing to get the most out of the software without wasting time doing unnecessary conversions for scaling.