TYPO3 Core

There are already two typoscript settings for determining the behaviour if an action can't be resolved:

mvc.callDefaultActionIfActionCantBeResolved = ...
mvc.throwPageNotFoundExceptionIfActionCantBeResolved = ...

These are taken into account if a called action is not allowed by the plugin. (for more info see https://docs.typo3.org/m/typo3/book-extbasefluid/master/en-us/b-ExtbaseReference/Index.html)

It also happens all the time that an extbase action is called without all the required parameters. This will throw an uncaught RequiredArgumentMissingException which usually looks like this:

#1298012500: Required argument "foo" is not set for Cyberhouse\Theme\Controller\BarController->list.

There are many cases where you usually want to handle such a case as an 404 error. To achieve that, you would need to override the default behaviour of the extbase controller, like override the processRequest(), catching the exception and doing the 404 handling in there.
For easier management I propose two new typoscript similar to the ones described above. This makes it possible to either globally configure 404 handling for missing parameters (config.tx_extbase namespace) or per extension/plugin via typoscript.

Example configuration:

mvc.callDefaultActionIfRequiredArgumentsAreMissing = 0
mvc.throwPageNotFoundExceptionIfRequiredArgumentsAreMissing = 1