I have not looked into the framework but I am guessing that most of the new Ace3 based addons are using a library to handle saved variables profiles, so I am posting this here.
If it's the wrong forum, I apologize. Maybe this is the responsibility of each addon dev.
Most of the new addons I have tried lately (many Ace3 ports/remakes of older Ace addons) have serious issues with their configuration profiles. Most of these addons do not default to the "Default" profile, which is quite simply absurd. If I need character specific settings for an addon then I can easily add the profile while making those changes. If I do not need character specific settings, then I am sitting here reconfiguring the same addon 10 times. Most of the "copy profile" mechanisms do not work right either. And if I want everyone to share a single profile, I shouldn't have to select "Default" on each one and then delete many profiles that have been automatically created for no reason. I have one character of each class, and many addons are creating 20+ different profiles. One for each class. One for each character. One for my server. And one called "Default" that isn't even defaulted to. Lately I've been configuring my addons by manually editting saved variables.lua because it's actually faster and easier than using the GUI.
If this has nothing to do with the Ace3 framework/libraries that the addon authors are using, then I apologize for posting this here. It seems that this is happening in almost every one of the newer Ace addons and it's really quite frustrating.
This has been discussed many times before, and you aren't going to change anyone's mind =)
Some people like it defaulting to be character, some people don't. No matter which way you go, someone won't like it. You just happen to be one of the people that doesn't like how AceDB-3.0 is setup by default. If the copy/change profile is not working, then that is something you need to let the author of the mod know about.