In reading over a lot of RPGs I have begun thinking about crunch and fluff in new ways. The paradigm I am using at the moment is to think of RPGs as having a puzzle value. That is, the ratio between how much of the game is focused around the players trying to think their way out of situations with concrete rules and how much is them just making cinematic decisions and the GM making something up.
Combat is the easiest venue for making these comparisons but it isn't limited to that. Some games have the players making decisions in a matrix of rules and numbers such that they could actually play out combats by themselves without a GM. DnD is definitely like this, as is Heroes By Trade. There are surprises much of the time but it would certainly be possible to list exactly how the fight will go and what the enemies will attempt to do and run it as a player quite comfortably. Whereas I remember a description from Numenera where the players were fighting a giant robot and due to something the players did the giant robot suddenly got a flamethrower. It didn't have one before, and that result wasn't planned... the GM just made it up.
Personally I find the puzzle aspect of such a thing completely lacking. If I have no idea what my actions will accomplish and encounters just go along until the GM arbitrarily decides they are over there is no optimization. I often take a sub optimal route of course, because once I know what I should do in the puzzle I need to figure out if that is what my character would do and often those are not the same thing. Without concrete rules to follow though the joy I get in sorting out a puzzle and finding the perfect solution isn't there. Heroes By Trade has a very high puzzle value in combat, possibly the highest I have seen, and certainly higher than most of the new wave of fantasy RPGs that focus on fluff more extensively.
That actually applies throughout RPGs including things like exploration and negotiation. I know the GM has to make everything up as they go but I want them to craft a world and then let me cut loose in it rather than have a blank slate. I like the idea of exploring the dread forest to find out what is there rather than the story simply happening no matter what it is I choose to do. Clearly the world isn't fully built when I step into it but I want to feel as though it is; I want a simulation as well as a narrative arc.
It is a tricky balancing act. In a pure simulation of course I would end up dead, eaten by direwolves in the dread forest. Either that or wander for days finding nothing of note! However, games that have too low a puzzle coefficient end up feeling pointless and contrived, like my decisions don't matter and thinking about things is irrelevant. I want the sense that the GM is simply letting me know what happens rather than that they are making it all up on the fly. I need the puzzle value to be high even when I do get a few nudges in the direction of something interesting.
I am by no means the extreme outlier in this. Naked Man is constantly pushing for poison tables, weather tables, and precise counting of coins. He wants to note that he has fourteen silver shillings, two golden dragons from the Free Counties, 87 brass pennies from Traevas, a ruby worth 80 silver shillings, and a golden statue of unknown value. For me this is simply too much because we never ever do it properly. If we were actually playing an economics simulation I would happily record gold and silver and such but we always end up fudging the cost of stays at the tavern or bribing the guards. Inevitably we spend time haggling over utterly trivial sums and hauling daggers from slain foes to sell for pennies, or we simply ignore the small expenditures and lose the simulation feel anyway. I have many times found a wonderful simulation feel for combat, for exploration, for discussion, but never have I found money to actually work that way.
Heroes By Trade is the game you would expect from me. It is crunchy in combat and has lots of interesting tactical decisions. It does not have a concrete money system and instead plays that fast and loose. It controls player magic and abilities reasonably tightly and does not simply let people make up things on the fly and hope the GM is generous. I want to have a list of resources in front of me and a problem to tackle. I want that puzzle to solve.