What do you think of the argument that it'll just cause more unneeded stress?
While I think stress is definitely a valid concern, I highly doubt it will actually cause a lot of stress to students. It is merely a test to see whether you are on par with the level expected for your grade, to make sure that students who are lagging behind sees where they need to work on and a tool to help them improve.
Anyhow, (unpopular opinion but) even if it does cause some stress, so what? Stress isn’t a bad thing, what matters is how you handle it. If one test which does not even determine much in the long run is enough to make you stressed to the point where it is a concern, then I think you would need more exposure to ‘stress’.
Not to mention the current setup of the GAT is practically useless for most students, it would be great if they could utilise the 3 hours (or 3.5) for something that actually means something. I’d rather get slightly stressed over something which could actually serve a practical purpose, than not getting stressed but still being forced to sit through 3 hours of a worthless test.
With your performance being used for future employers in the hiring process, I think that’s (to an extent) perfectly valid. First, it’s not as if your chances of getting hired ONLY depend on your result (it only serves as an indication); and second, I doubt any employer would require you to score an extraordinarily high mark to hire you, rather it’s more of a “making sure you’re not illiterate” kind of thing.