Back in the 80's, I bought my first cordless drill, a 9.6 volt Makita. After that came 14.4 volt and 18 volt Dewalts. Each step got me more muscle and longer run time, which was offset by the penalty of additional weight and bulk. Now, the one that gets the most use is my 12v Bosch Pocket Driver, since it's just so damn convenient for small jobs or on a ladder. This may sound off the wall, but think about it for a minute; How about a hybrid cordless polisher? You could have a big battery, up to 40 volts that you'd set on the floor, with an 8-10 ft cord to the polisher. You'd get the benefits of power and run time without having to support the weight on vertical panels and a short cord would be a lot easier to manage than a 25 or 50 footer.
Maybe I should apply for a patent and a seat on "Shark Tank"!
Bill