"Memorial" is one of those episodes you can absolutely skip, as it really adds nothing at all.
Generally speaking, it's a standard message about the horrors of war, and maybe on that level it might be viewed for comparison with the number of times, say, Deep Space Nine did it (as early as its first season), but it's just so generic and doesn't even have a strong central if random lead role like "Nemesis" did with Chakotay in the fourth season.
So here's one you can skip.
franchise * series * essential * character
Memory Alpha summary.