By now, the operation of this software should be efficient. I can understand the addition of new features and improved functionality, but it looks to me like there are operational changes made in each version. Once you find the simplest operation, then make it standard. Operations that are consistent through multiple versions should not be changed unless they absolutely HAVE to be.
Also, I get comfortable using a specific set of instruments in my writing. Its great to add more, but do not replace the old ones with a different version or remove what has been there for previous versions. The addition of new sounds makes me nervous that I may have lost my favorite instruments or they sound different.
I know people who have very old versions - version 12 and 9! They refuse to update because of these issues. This tool is most useful when you don't have to re-orient yourself or re-learn the functions / sounds that you are accustomed to using. I will not update from my current version until I know the learning curve will take minutes - not hours.
Maybe MakeMusic can offer a download and install that will run for 1 week to just try it out? As long as the older version(s) don't get clobbered in the process, this may make it easier to see what the upgrade is like. They can charge the credit card after one week after the download if we have sent an approval code?