This war is also notable as a '
precursor' to
World War I's land battles. All of the elements that made World War I such a
lethal stalemate (poor logistics,
machine guns,
trench warfare,
artillery duels) were utilized or came about in this war. Not only that, but most of the major European powers actually had observers present for this conflict, who wrote home about the things they'd seen.
Despite all this, the outcome of the opening battles of World War I seemed to catch all those involved completely by surprise. It was not predicted that static, trench-based fronts would develop; nor that the machine gun would offer the defense a huge advantage over the offense, nor that logistics constraints would prevent large, fast troop movements much past available railheads. This is merely a component of the many Big Questions about World War I, the most interesting from a tactical standpoint being 'how did everyone get their predictions of the effect of the introduction of the machine gun so very wrong?'
The Russo-Japanese war shows us that there was a deeper problem than the typical 'fog of the future' and lack of information - even when the information was available (and graphically so, for those who observed this conflict) it wasn't assimilated into the worldview of those gearing up to fight with these new weapons and tactics.