back on the ps2/xbox there was a depth chart as well as a formation subs. i would could change who lined up for every individual formation. packages are like the dumbed down version of this feature. when i played, i could change my kick off team to all of the fastest available guys and kr would be the better blockers out of the guys available. also on defense i had speed formations and then strength so when i wanted my big boys in i would pick a 3-4 over and for my faster guys i would pick 3-4 under and for the best players at every position i would just put 3-4 normal.
i agree that there should be some versatility rating for players of similar positions but then again they can have playbook specific positions so you will get your h-backs and situational rushers as needed