Another issue is that lets say something is unclear in the law (like with DACA where a hole in the language allowed someone that entered prior to turning 16, stayed a bit, left, and returned over 16 to apply).

Issues like that are resolved by immigration courts in removal proceedings and cases revolving around large issues in law do end up before the BIA. Don't forget that 245(i) was about 10 lines of text and there were 5 precedent decisions clarifying how it all works, with several others touching on the issue without it being central.

In some cases the cases would go before Circuit Courts of Appeals and in rare cases all the way to the Supreme Court. There were also cases where USCIS would enter into settlement agreements after an unfavorable circuit decision or a circuit split. Other cases would get bounced around, IJ denies relief, appeal to BIA, BIA denies, appeal to Nth Circuit, Nth Circuit rules that BIA abused discretion and remands, BIA remands back to the IJ to reconsider the case consistent with whatever the Nth circuit ruled, which may again be appealed. Some cases go through appeals and remands for years.

Now I don't feel like going through this republican authored smut so lets just take the employment requirement, you lose it if you're not employed for a period of 1 year. Now, is it 1 year total, 1 year continuously, what counts as employment? Would working a Saturday only job satisfy the requirement? There's no definitions so it's up to USCIS to fill in the blanks with regulation. You fail those you have no appeal rights (maybe AAO will reconsider your case but that's about it), there might not even be a regulation so an office in Elk's Ass, Wyoming is denying as many as they can, while place like San Francisco, California adopts a much more favorable procedure, so now you have two different applications of the same federal law with no way for you to challenge it.


Personally I think that limiting judicial review should be unconstitutional, but when that issue came along a lot of courts just snuck out the window.