The recent removal of the quasi-official
node_validate_title() function from 4.7 causing various errors with contrib modules, I wondered whether there wouldn't be a way to trap such errors in a way that would be helpful to newbies, instead of the current situation where all they get from their newly haphazard drupal install is a PHP fatal error.
The idea, then, is to register obsolete functions in some form of legacy maintenance module, to generate a useful help page pointing the user to a doc page on drupal explaining why there is an error in his configuration and what he should do. In
node_validate_title()'s case, the help is a bit succinct: http://drupal.org/node/22218#node_validate_title.