Identification of the "remnant" was critical to Joseph Smith. Although we've discarded the issue, it was of central concern to the early Brethren. So much so that the "remnant" was what drove the movement westward near the "borders of the Lamanites" The first missionaries were sent to the "Lamanites" as part of the Restoration's concern with the promised "remnant" of the Book of Mormon people. (See D&C 32: 2.) The Saints were required to move west to be near these people as part of locating Zion. (D&C 54: 8.)
The Book of Mormon is filled with promises addressed to the "remnant" of those people. Modern revelation promises they will blossom as a rose. (D&C 49: 24.)
The first Temple built in the west after the exodus was in St. George to be near the suspected "remnant" to be reclaimed. The first company in that Temple's first session included a Chief from the Hopi tribe. Brother Nibley was partial to the Hopi as the "remnant" or at least a part of the "remnant" and he wrote a good deal about them.
This is an important subject. Worthy of study. But it is too great a subject for treatment in a limited venue like this. To do it justice would require this forum to become devoted to that subject for many days. By the time it was finished, I doubt anyone would still be reading. So I'll just reaffirm the subject is important, and there are many passages in the Book of Mormon dealing with the "remnant" of the Book of Mormon people. Promises extended to them have not yet been fulfilled. But all those promises will be fulfilled. As they are, the role of those people will change from what we see it today into something much more central to the Church.