I think you make good points, but I think you highlight the issue for Marquette this season, the starting 3 for St. John's is a top 50 player and ours is a former walk on. You suggest that it's not fair to compare them because one was highly rated and one wasn't, but I'd argue that the original statement that kicked this whole thing off was to compare the talent level of the teams we face down the stretch, and by that statement alone you proved the point the OP was trying to make. We simply have a less talented roster this year than the other teams we are facing.
Also I still count Thomas and Harrison as back court players as both teams run multiple 3 guard lineups, just because 5 guys are on the floor at the same time doesn't mean they fit into the 1,2,3,4,5 mold...