I aren't saying untimed content has no place, but the general consensus is nothing should ever be timed on these forums.
I am just trying to say a well designed dungeon forces people to use stratagy, especially how instances in FFXIV work with your return sending you to the start, it just makes everything easy mode with no time limits.
The only way to add any stratagy with no time limits is setting return to your HP in instances rather than the start then it would mean you need stratagy, but it would be 1000x worse than time limits because one wipe and your out.