People need to accept the reality. Also, FFXIII allows you to move the camera.
- What can you do while standing still in the linear paths of FFX? Nothing. - What can you do while standing still in the linear paths of FFXIII? Move the camera to check out the stunning art direction and vistas.
Back tracking FFX means **** as you aren't seeing anything new. At least in FFXIII, you can always stop and take your time by moving the camera to observe the scenery. Not only does FFXIII have less linear map design than FFX, but you can move the camera to observe your complete surroundings. There's also more to do in the linear maps of FFXIII as there's more branching paths and side-paths leading to treasure chests. It's the less linear feeling game.
For the record, battle system, character growth system, NPCs, towns, shops, blitzball and end-game content all have nothing to do with linear map design. Talking map design only, FFX is undoubtedly more linear than FFXIII.
Final Fantasy XII is a masterpiece in both game design and story.