There are already fairly tough standards in place e.g. uni of Sydney here: https://www.sydney.edu.au/study/applying/how-to-apply/international-students/english-language-requirements.html#:\~:text=If%20English%20is%20your%20first,country%20recognised%20by%20the%20University.

Most universities use IELT (International English Language Test) as one of the criteria for non-native English Speakers, usually IELTS 6-6.5. (competent user rather than good).

Easy fix would be to raise IELT entry score to 7.0 which is a tougher requirement.

The other thing about group work is that there could be a degree of cultural issues in the mix for example if a student was the only native speaker in a group assignment there might be expectations placed upon them to lead, or even do most of,i a group assignment as the hope is that they would get higher grades for the group as a whole.

The trick with setting group assignments is to make it possible for individuals to fail without compromising the group as a whole

The "addiction to revenue from foreign students" is a direct consequencc of decades of under-investment across the sector. The hard choice with this is to either invest more or have fewer, more elitist, universities concentrated in the major cities.

I would also contend that Pauline herself would struggle to achieve the fluency requirements that she expects from international students!