I think I know the answer this but I will ask anyways. Besides the two compact drills, how many of the new 20V Max tools are really newly designed tools and not just current 18V tools with updated handles and electronics to accomodate the new slide pack batteries?
All of the tools have more changes than meet the eye, but you are right, the hammer drill, sds drill, recip and circ saw are very similar to the 18v system at this point. The impact drivers are different, and obviously the brushless is completely different. You will see the differences become more substantial as new phases come out.