If Quist wins or just comes closer than Ossoff, that will have profound implications for the Bernie strategy vs. the Clinton strategy, particularly if KS-04 ends up closer than GA-06. In other words, if Ossoff actually is mired in the 30's, it should be taken as an early indication Clinton's massive overperformance in the Sunbelt suburbs was a one-time thing. The KS and MT races being close would suggest it is possible to get enough rural voters back.
It should be noted that Thompson in KS-04 did terribly in the rural areas. He mostly made up territory for Dems in urban/suburban Wichita. Democrats do need a better rural strategy--with one we may have, in fact, won KS-04. The rural South and Plains, however, are going to continue to be deadzones. If we can consolidate control in the Pacific West and Northeast; make progress in traditionally conservative urban/suburban areas like GA-06, GA-07, TX-32, and TX-07; and hold our own in the rural West and rust belt, that, it seems to me, is the best route to a majority.
This either Hillary OR Bernie strategy stuff is nonsense. It has to be BOTH suburban D-growth areas like Orange County (CA) AND populist ancestrally Democratic areas like rural Minnesota/Wisconsin.
If Quist wins MT-AL, it will show that a populist Sanders-oriented strategy may work. While Thompson was certainly more of a Sanders Democrat, his performance relied more on a Hillary+ coalition than something Sanderseque.
Actually Thompson's swing from Trump in Sedgwick County was almost exactly the same as his swing from Trump in the district as a whole.
Sedgewick county has like 70% of the vote in the district, so it would be very surprising if its swing didn't closely match the overall district's swing.