I have a similar sentiment regarding Windows 10 or IE 11 or Office 2016 . . . I actually had no issue with XP, but it had security problems. I'm not all that excited over the new user interfaces and features that are added to each version. Eventually, though, there will be no choice. XP is no longer viable and eventually Windows 7 will become obsolete.
100c at some point will be the only version, and subscription will be the only licensing model. We have no idea what the cost will be in two years to convert (after it has many more added features that were not added to 100). It may not seem like much has been added, but the plan is to provide much more. The reality is that it was prospects who asked for the new look (or voted by rejecting 100 and its tired look), not existing users. It's a start.
I don't agree with the customer's response. In addition to maintaining operating system compatibility, there have been many useful enhancements over the years, including integrated and connected functions that the market has asked for. I would agree, however, that the amount being charged for annual maintenance is too high, and that Sage should have an option that does not include their telephone support.