Currently the IDE integrations need to perform 2 steps:
1. load the POM with no validation in place. Having a MavenProject instance in the most cases possible is important.
2. to display the warnings in pom editor and elsewhere one has to run at least the projectbuilder/modelbuilder with proper validation level and collect the results from either the result object or the exception thrown.
The proposed patch in https://github.com/mkleint/maven-3/commits/trunk makes it possible to have both a MAvenproject instance under minimal validation constraints and collect the validation problems for any higher validation levels.
Additional benefit of the patch is that it logs "since what version of Maven is the problem valid". Which can be further used in both cmd line and IDE error reporting.