I would imagine that this type of door was installed to save on swing space or lack of any space for a door to swing.
Imagine a swinging door there, see where it is when open. Does it block anything important to get to?
If you determine that the reqular swinging door is OK, then you must re work the structure to accomodate the regular door supports and jamb.
The wall that the pocket door rests in is much wider than the side jamb of a regular door, so you do have some reducing to do. I would not in any way consider this a easy diy task. I would hire it out or refirb the pocket door.
I would guess without seeing, that the pocket is there for a definate reason and it would benifit you to leave it as it is.