Correct me if I'm wrong, but isn't most of the backlash just saying that the War of the Eight Princes isn't really Three Kingdoms material? The plot of the Three Kingdoms hasn't been resolved so it might have seemed like skipping to Eight Princes is premature. It has also almost never been represented in ANY popular media, be it games or tv shows.

The War of Eight Princes isn't primarily a militaristic war, but a series of political struggles. You could say that any military maneuvers are only extensions of politics. Prince Zhao killed Prince Huainan through an individual assassin; the defeat of Zhao and Hejian by Qi and Donghai respectively depended on large internal alliances; Changsha died to rebellion; Runan, Chu, and Qi all died to palace assaults. There were no long-term sieges or large scale recruitments so the scale of warfare was relatively small. It is also not a continuous period, but there were period of temporary peace short or long, and was only later summarized into one "War of Eight Princes" by Tang historians.