I don't think they'll arbitrarily change the terminology, and ditch WR1, WR2, etc but could see them supplementing the depth chart slots with some of that data. Isn't x, y, z playbook related anyways? What NFL team's depth chart lists their 1-3 x, y and z receivers? Special teams probably would be addressed in that way too, at the playbook level rather than supplemental depth chart positions that might not even exist today, or do they? We have what we have now in part because here is what NFL rosters look like:
http://www.dallascowboys.com/team/depth-chart
Honestly, I think some of this stuff will be addressed in the next year or two, with how this team is tackling things. The next real deep dive into franchise has to hit on rosters and contracts for sure.