1. On the test project I have been using, Scripts.rxdata gets reduced from 281 KB to 160 KB.
2. Without the compressor, that is mostly true.
3. You can see believe it when you see it. Although 90% is not typical, it usually averages about 30-40 percent. There is no change to the quality of the image.
4. The stronger Zlib script compression is marginal, only a few KB for an entire script file. I am simply using Zlib::BEST_COMPRESSION, which RM might be doing already, but in an older version of Zlib.
5. Actually ARC inspired me. Working on the editor I encountered the problem of how to handle it when the currently defined data for something was erased (ex. Actor's starting weapon was erased from the Weapons tab). I handled it correctly in ARCed to notify all relevant windows when a database item is changed, but I realized that this can occur in RM while making a game and the user might not realize it.
The point is to make a single, all encompassing, resource testing and optimization tool. There are plenty of topics of various scripts to use (including yours

), file compressors, converters, etc, etc. This will be a single program that can automate it for you, and be much more thorough. Instead of just giving a log of used RTP resources, it gives the option of copying them for you. Instead of just notifying of unused resources, it gives the option of finding and removing for you. There are backup and archive tools included so that when you open a project, it prompts to create a backup for you, so even if something goes wrong, no harm is done.
Given, it is still up to the user to ensure their game is bug free, but this program can do 95% or more of the work for you.