Thornfall Alliance and the Dhunian Archons

I don't think I ever really had a problem with Midas's Fury in Thornfall. Farrow infantry is accurate enough that you don't always need Death March for the +2 Mat, and you've already gained the Vengeance benefit by the time you've got to decide whether or not to upkeep. Plus the list is so slow that by the time you need to decide whether you should be casting Battle Lust, you've surely already lost a Warbeast or three. I don't think Midas in Thornfall is a bad list, frankly, I just don't enjoy the way it plays. Too slow and reactive and without any cute tricks. I'm considering toying around with some Meat Thresher builds in the near future, but I don't expect them to become part of a tournament pair anytime soon. The Dhunian Archons help, though it's hard getting them and the Razorback Crew for some board presence and the critical mass of infantry and the Meat Thresher all in the one list.

Other than that, I think you've nailed the problem with Thornfall in the lack of Warlock-infantry synergy. Poor scenario presence doesn't super help, though there are comparable themes like Exemplar Interdiction that are mostly limited to Speed 5 infantry. EI has Desperate Pace and AD Errants and Warcasters who actually speed up their infantry and access to resilient multi wound infantry though, not to mention a gun platform in the Judicator. Thornfall would need a fair few new releases to compete on the same field.

when your only tactic is "run forward and hit things really hard"
you tend to walk into a series of problems.