Alright, here's what I think. First of all, this...:
Student One:
-4.0 GPA, some school/community college
-17/17/18 (AA/TS/PAT) DAT
-Some dish-washing "research" experience
-Practically no EC's
-Letters talking about how this student got an A in the professors class
-Somewhat shy
Student Two:
-3.1 GPA, competitive undergrad program
-24/25/22 DAT
-Multiple Research Publications
-Letters sincerely discussing student's maturity and intellectual ability
-Outgoing
-Personal statement explores impact of some personal obstacle (i.e. working while in school to support family) that impacted academic performance
...is complete baloney. Wonder why, let me demonstrate by tweaking it a tad:
Student One:
-4.0 GPA, some school/community college
-17/17/18 (AA/TS/PAT) DAT
-Multiple Research Publications
-Letters sincerely discussing student's maturity and intellectual ability
-Outgoing
-Personal statement explores impact of some personal obstacle (i.e. working while in school to support family) that impacted academic performance
Student Two:
-3.1 GPA, competitive undergrad program
-24/25/22 DAT
-Some dish-washing "research" experience
-Practically no EC's
-Letters talking about how this student got an A in the professors class
-Somewhat shy
Now who will you take? Suddenly it's not so cut and dry is it. It's not all about the DAT, or all about the GPA, or what school you went to. You can come up with all the different scenarios you want, and if your DAT>GPA, then chances are you'll lean towards the "some schools are easier than others" and if your DAT<GPA, you'll probably lean the opposite way.
Sure, Bachelors from Harvard looks nicer than the same degree from, say, your typical state school. But is it fair to say than one is more difficult than the other? In all honesty, unless you've gotten degrees from both, then you really can't go much beyond speculation. Such a speculation may have place when comparing a 3.4 from Harvard to a 3.6 from StateU.
Take someone like me, who went to his state school, which is world renown for its....meteorology program...Yay... 19/19/17 DAT, 4.0 GPA, 2 external grants, 2 publications, 4 years research experience with 3 competitive summer biomedical research programs, about 15 paper and poster presentations...and that's just the tip of the iceberg...Put your 3.1 with 25/something high/something higher from Cornell and see if he/she can do better. My "bragging" if you want to call that way (meaning you totally missed the point) only shows one thing. Look at the whole picture. There is a reason why the application doesn't only consist of 3 lines: DAT, GPA, University.
Be open minded...