Random game design/GM thought.  It's not specifically Fate-related, but I generally like the community here.  So there.

It seems like most players have a certain... call it 'cognitive load range'.  That is, they want their cognitive load (decision making, etc.) to be somewhere between the low end and the high end of that range.

Players may also have types of cognitive load they prefer, but so long as they're doing things that are within those preference, my is that the range is relatively static.  Perhaps even more importantly, players will change the games they play over time to meet their preferred ranges_, either by houseruling, excluding things, or focusing on certain things.

This has a couple of interesting ramifications, if it's correct.  And it also kind of predicts some things that we've seen in the game industry, so that's interesting, too.

The first ramification is this:  If a given game (system + people at the table) has too low of a cognitive load for the players, they will correct this, either by adding in additional load or abandoning the game.

The second ramification is the opposite of the first:  If a given game has too much cognitive load, players will correct this by either removing things or abandoning the game.

Okay, so a practical example.  So, in practice, one trend that started in the 80s and has continued is the increasing focus in many RPGs on linear 'encounter-to-encounter' styles of play.  DragonLance is an obvious early example, and many organized play modules follow that pattern.

The result of this has been a shift away from players making larger-scale in-game decisions - where to go, what to do, etc.  Strategizing and scouting are de-emphasized by this style of play.

So, if my hypothesis is correct, this would lead to an overall decreased level of cognitive load - players having lost decision making capabilities in terms of the direction of the game.  So, my hypothesis would then predict that this cognitive load would be increased in other areas - and indeed, over this time period the game systems have become more 'crunchy' and detailed, both in terms of play and character build.  This may of course be a coincidence, but it's consistent with what the hypothesis would predict.

A bit of possibly more useful Fate-related fallout from this is pretty simple - since Fate is, mechanically, a very simple game, the cognitive load for players has to come from areas besides the game mechanics.  In other words, the player has to be given dilemmas, or interesting plot-related situations, and needs to have a greater influence on what happens to make up for the reduced mechanical grit.

An interesting case study of this is FAE Pathfinder.  While I'm generally skeptical of attribute+skill systems, or "crunchier" Fate in general, FAE:PF's goal is explicitly to enable the usage of Paizo materials, including Adventure Paths.  Because of this, and the lower levels of agency typical of module series like Adventure Paths, the cognitive load has to be made up somehow or the game will be very, very boring.  In this case, increasing the mechanical "crunch" - the cognitive load from the system mechanics side - is absolutely the right thing to do.