This is why I go with the defaults, except for content (which is what takes up the most space). SONAR also has folder preferences which can save megabytes by putting templates, track icons, etc. elsewhere.
 
Obviously CCC could be streamlined, but there are also contradictory desires. When Foxboro showed up, which needed to reinstall pretty much everything to be compatible with improvements in the upcoming CCC, there were a lot of requests for an "Install All" button. That was actually the mindset of how CCC started, but then people wanted a more granular installation experience, e.g., installing only core features or only selected content, so Cakewalk created more categories which accounts for the re-scanning. So we'll see what happens with the update, but I suspect that the CCC will continue to evolve, just like NI's Service Center (which I think has gone from a PITA to a very valuable feature of NI's software).