I actually have JOK ranked higher than Simmons because of size and length. Simmons also really played well in the second half of the year when the Cardinals started having him do more traditional MIKE things and less safety things.
To your point, what JOK does so well is adds another piece that can play in multiple positions. Troy Hill can play slot or boundary, JJ3 and Ronnie Harrison both so lots of linebacker-y things, JOK can play linebacker or safety, Walker can play the MIKE, SAM, and WILL, Clowney, Jackson, and Myles can all play inside or outside, etc.
The defense is incredibly versatile. Woods has no excuses this year.
Adding to the Cardinals talk, Simmons was terrific the last quarter of the year, and the first half he barely even saw the field, because they asked him to do WAY too much, essentially be in rooms for three different position groups. Once Vance Joseph figured it out, you saw glimpses of what’s going to make him incredibly successful.