I started a thread sometime last year asking why we carry a long snapper, what makes these guys so unique that one of these other world class athletes can't get good at it. In the old days, it was either a center or a TE or a LB who did it. Nowadays, since they can't line up over center you could even have a Steve Tasker type of guy do it because the main part of the job after snapping for a punt is running down field and head hunting.
There's a reason we don't have a holding specialist with his own roster spot. Used to be the backup QB did the holding but now it's almost universally the punter, probably because he has more practice time available to work with the kicker.
If we were to tie down an extra roster spot for a special teams guy, it would make more sense to have a kickoff specialist who can boom touchbacks all the time.
But my preference would be to go the other way: turn your kicker into a punter so you only carry one specialist on the 53 man roster, and free up the P and LS spots for other guys who can fill in but can also play another useful position in a jam.