Good analysis, Weldon. I would add a couple of things:
1. Although Shalane's relatively slow times on record-quality marathon courses can be explained away to a significant extent by the tactical nature of those races, and her seventh-place finish at Boston can be explained away to some extent by her decision to, in effect, rabbit the race for the lead pack as long as she could (about 30K, I believe), I don't believe that she's ever run any especially fast times at any distances above 15K, despite quite a number of half-marathons during the last five years in addition to her marathons. Maybe there are good reasons that she has never broken 68:30 for the half, but that's not a stat that would typically suggest a sub-2:20. Also, losing over three minutes to Jeptoo and two minutes to Deba over the last 12K or so at Boston isn't particularly indicative of sub-2:20 ability on a record-quality course.
2. On the flip side, having at least two personal male pacers is huge, and not merely because they may keep a governor on her pace. As a matter of physics and physiology, it's worth a lot. (Berlin's heavy reliance on pacemakers is also the main reason that I don't find the race to be especially interesting, especially on the women's side.)
All in all, I'm a bit up in the air about Shalane's ability to break, or come close to, Deena's AR. The race conditions (including personal pacers and a superfast course) seem likely to be close to ideal, and her 10,000m and cross-country accomplishments suggest the ability, but her road-racing history does not. If I were betting, I'd probably go with the road-racing history.