In all seriousness, those URMs that I knew who had problems had the biggest problems and struggle with the MCAT.
The MCAT is one single barrier that seems to get a lot of people at my university regardless of status as minority or majority but the minorities especially those who came from a foreign country (i.e. Haiti, Dominican Republic, etc.) and those who came from disadvantaged areas like parts of northern and central Florida where educational resources were not as easily available. In turn, I found that a lot of these URMS struggled most with the Verbal but to an extent also in the science sections of the MCAT.
Volunteering, research, clinical experience, etc. are easy to obtain. Grades, again are not that hard to keep up if you have good study habit. The MCAT, however, is in a class of its own and if you are not someone who at some point in their life was an avid reader or not someone who's just a naturally good test taker, the MCAT is a major obstacle to overcome. Most minority students that I was friends with and that also struggled were people who struggled with the MCAT most above all else.
I disagree, research experience is not easy to get for everyone. First you have to find a professor that is willing to spend their time, or their techs time, to train you, as well as develop a project that is suitable for you to do, then answer your questions, advise you, proofread your technical submissions, etc. I know alot of professors that are unwilling to do this because of the pressures to publish and obtain funding, especially for young professors who are trying to establish themself.
Clinical experience may not be difficult to get, but substantive experience is rare. I volunteered at a hospital for 4 months before I realized that what I was doing was not helping me at all, I rarely saw doctors, had limited contact with patients, and mostly just followed around the nurses and emt's. Now that was my fault for wasting my own time, but now that I have that experience I can recommend better options to those I advise. Even if you have an emt or CNA license, where I live there are so many of them, mostly hs grads who want to do that for a living and not just as short term experience, that working in a hospital is out of the question unless you know someone.
As for grades, you said it, "if you have good study habits" which many people don't. Should they be denied access to medical school due to bad study habits? Then that could be a focus of the program, establishing stronger study habits among premed URM's.
I do, however, agree with many of your points concerning the MCAT, and by looking at the poll, that is so far the most commonly experienced roadblock. I especially agree with the comment that the MCAT is a large barrier to URM's and non-URM's alike, it makes me think I should post another poll that asks non-URM's what their biggest roadblock is. It would be interesting to compare, and see if the needs are the same or different. I appreciate your commentary, and that of others on this forum who attempt to keep the discussion on the topic at hand, common roadblocks for URM's. Let's keep it positive.