I think it’s smart to think about the incentives of the admissions officers — but I think it’s a bit more complicated than just maximizing GPA to boost the rankings. Yes, absolutely, they want to increase their GPA and LSAT medians. But they also want to admit people who will pass the bar and get full-time legal jobs (which also factor into the rankings). And they want people who might get federal clerkships or biglaw jobs or prestigious public interest fellowships. They want people who will have successful legal careers and who might one day donate to the law school. And to some extent, I think they want people with some interesting backgrounds who might bring something unique to classes.
So, I’m not disputing that GPA and LSAT are by far the most important factors. A garbage GPA even from a prestigious school is probably going to sink an application. But if you have a 4.0 GPA in basket-weaving from a local commuter school versus a 3.7 GPA in engineering from MIT – I do think the admissions officers are going to be weighing factors beyond just the raw GPA.