Would it be possible to move the configurations in init.php into a seperate configuration file (or make them ACP settings) ?

Because, things like the admin path (which incedentally it should be mentioned in the upgrade instructions needs renaming before uploading if you've renamed it) have to be reapplied every upgrade, as init.php is changed every upgrade (because the version numbers are in it)

The settings which need to be maintained are IPB_ACP_DIRECTORY, IPB_ACP_IP_MATCH, maybe IPB_ACP_ALLOW_EXEC_URL, IPB_ACP_ALLOW_TEMPLATE_PHP, IPB_MAKE_PORTAL_HOMEPAGE, IPB_ACP_USE_GZIP, maybe KERNEL_PATH (why is that even an option?), LEGACY_MODE, USE_MODULES, CUSTOM_ERROR. The rest like IN_DEV you'd probably only enable temporarily.

That would make sense to me, although the root path has to stay as that's how it finds the config file.

There are some settings that you really wouldn't want in the Admin CP for security reasons, and I feel that will be the answer IPS will give.

IPB_ACP_ALLOW_EXEC_URL - Its recommended to be 0, allowing someone to turn it to 1 at their own will in the ACP isn't the best thing
IPB_ACP_ALLOW_TEMPLATE_PHP - Self explanatory, meant to be 0, if a admin turns it to 1, they can enter PHP in templates, security risk

Yup - certain things you wouldn't want in the ACP. But they shouldn't be in init.php either

If someone for whatever reason has allowed PHP in the templates - that setting will revert back to 0 when you upgrade (because init.php always has to be updated) - which is probably going to mess you up as you must have enabled it for a reason. So that one needs to be in a file, but not init.php

The thing which is actually annoying me is IPB_ACP_DIRECTORY

Already in the works. Probably, the version numbers, which is why init.php has to be replaced in the first place, will be moved elsewhere. Additionally, if you have to bump the memory limit up, or enable display_errors, init.php is the best place to do it, because that file is basically loaded everywhere..

Technically, what does that change?

More secure, speed increasing....?

Nothing, it just means you won't have to re-perform common edits when upgrading.

Thanks Professor P