Well, "clutch" is already in the game and has been for years. There's been no change to that as far as I know.
I don't think there's a toggle to turn quirks on or off, so we're stuck with them no matter how "sim" they seem. I do sort of like the idea of adding a bit more strategy to team building--if you already have 5 position players with the "road warrior" quirk, are you really going to sign that marquee free agent that is also a "road warrior" or go with a "homebody" for more balance? Stuff like that is cool and I believe that real front offices do add that type of peripheral detail into their decision-making.
I still think splits/quirks can be done right and "sim" if the data set is large enough. But, if you are expecting 40 ABs or whatever to tell you anything deep and philosophical about a player's true abilities, then think again.
The bottom line, however, is even if a quirk gives you a fractionally better/worse probability at a good outcome (bigger/smaller PCI), the user still has to execute a gameplan. In that way, the user still retains most of the control and "sim"-ness of the experience.