I agree! A percentage of completion shown on the main download page would be great! Or just something to show people how far development is. If there's anything I've learnt in my career, it's that people don't like to be kept out of the loop or uninformed about something they invest a lot of time into. People like to see progress.
This would be beneficial to people so they can clearly see progress, and it would be beneficial to the devs because it would lift a weight off of their shoulders by not having to deal with people constantly asking about progress or if it's done yet.