Compared to Fate Core, WotA is intentionally heavily constrained. There is an action economy in scenes that isn't present in Core. However, it's still probably worthwhile to make WotA as close to Core as possible unless I can think of a good reason otherwise.
Some of the changes, like number of stress boxes and consequence tracks, should be fairly easy to port over. That may require lowering the difficulty of missions, however, but that shouldn't be too hard.
The stunts section was illuminating. Some of the stunts in WotA currently don't fit the desired Fate design pattern, in that they would see use too much. They're more general bonuses to rolls, which Fate Core suggests be used with the expenditure of fate points. The demarcation between stunts and developments is an area in WotA that needs to be thought out better in general.
Also, Fate takes a more standard approach to stunts in general, as they don't have costs anymore, but rather all fit the same power level. That might be tricky in WotA, as magic is modeled as a stunt, and magic is more powerful than one stunt slot at the moment.
