Wouldn't future scenarios benefit from a doom track system that's separated from number of turns? As it stands now, most (if not all) scenarios follow this formula: You spend turns collecting requisites and, optionally, clues to help with tests, at the expense of the ratchet ticking one step ahead towards a predetermined critical point. Each scenario is strictly timed: If you don't do x before n turns, there's a worse outcome/changed resolution/game over. n is a constant. Player actions can't change this, except presumably if an action hypothetically triggers a whole new ratcheted sequence/board. Wouldn't it be more flexible if, alongside scripted events happening at this or that turn, there was a AH-esque doom track? It doesn't even need to be articulated; it's probably for the better to keep it under the hood, and then the script can give cues when and if appropriate. This way, you could build scenarios that follow a very different structure and where player agency can become more important at the script writer's wish. Most importantly you can, as a player, buy time (what will it cost?). That's a meta-move that i'd really like to see in the future.

edit: it's not really a "vs.". They work best complimentary to each other and you have the benefit of applying different logical gates to the two for different effects and designs.

There are some examples of this being used. It doesn't directly affect the games outcome though. In Vengeful Impulses it uses a clock mechanic to tell you how long you have until dinner. It's as easy as an End Round implementation to display how close your are to the end of an event.

I thought the timer in vengeful impulses was just the usual ratchet-style "event happens when number of turns reaches x"? As opposed to a threat counter which increases/decreases by one or more conditions being met (as delfined by the scenario).

That could be. I know that they could use variables that increase per event. It's a pretty solid mechanic that whenever an explore token is used add one to a variable. When variable equals some preset figure, then boom.