The original construction here in 2 Nephi 11:8 reads perfectly well even if it is technically ungrammatical. In his editing for the 1837 edition, Joseph Smith removed the relative pronoun which, but the resulting text is actually more difficult to comprehend. Normally in the text, when the relative pronoun whoso(ever) is the subject of a wh-noun clause, the predicate in that noun clause immediately follows, as in 2 Nephi 26:32: “for whoso doeth them shall perish”. There is no difficulty, of course, in understanding such wh-noun clauses. But here in 2 Nephi 11:8, there is an intervening prepositional phrase (“of my people”) between whoso and the noun-clause predicate (“shall see these words”). If the prepositional phrase had been missing, then “whoso shall see these words” would be the expected phraseology, definitely not “whoso which shall see these words” (or “whoso that shall see these words”). But given the intervening “of my people”, the reader is helped by having the relative pronoun which there.
Elsewhere there are only three cases where whoso(ever) is not immediately followed by its predicate:
In each of these cases, whoso(ever) is postmodified by a prepositional phrase. The first of these (Mosiah 4:28) was originally like 2 Nephi 11:8 in that its prepositional phrase was followed by a relative clause (“whosoever among you that borroweth of his neighbor”). The relative pronoun that was deleted in the 1920 LDS edition, but the RLDS text has retained it. Unlike 2 Nephi 11:8, this example in Mosiah 4:28 was not edited by Joseph Smith. In contrast to the cases in 2 Nephi 11:8 and Mosiah 4:28, the last example (3 Nephi 18:13) is one that has always conformed to the grammatically preferred style: there is no relative pronoun such as that after “among you”, although it would read more easily if there were: “whoso among you that shall do more or less than these are not built upon my rock”. Finally, the example from Helaman 6:24 is more complicated than any of the others and appears to have one clause with the relative pronoun which and one without any relative pronoun. Even this example would read more easily if there were two relative pronouns: “whosoever of those which belonged to their band which should reveal unto the world of their wickedness and their abominations should be tried ... according to the laws of their wickedness”.
Obviously, the original text allows both possibilities for this kind of complex whoso(ever) clause (either with or without the relative pronoun after the postmodifying prepositional phrase). The critical text will in each case follow the earliest textual sources. In 2 Nephi 11:8 and Mosiah 4:28, the relative pronouns (which in the first instance, that in the second) will be restored.
Summary: Restore in 2 Nephi 11:8 the relative pronoun after the postmodifying prepositional phrase in the whoso clause (“whoso of my people which shall see these words may lift up their hearts”); similarly, the whosoever clause in Mosiah 4:28 should read “whosoever among you that borroweth of his neighbor should return the thing”.