Because the original wasn’t hard enough, wimps
Long War Studios, the fellers wot brought you the Long War mod for 2012’s XCOM reboot, are replicating those actions for the sequel. A rebranding has led to the team calling itself Pavonis Interactive, and its official site mentions both Long War 2 and its Kickstarted original creation, Terra Invicta.
If you’re unfamiliar with the Long War mod, here’s a primer: bigger squads, more of a focus on fostering an entire roster of soldiers instead of picking favorites (due to fatigue and injury systems), a much longer, grueling campaign, and all sorts of new weapons, classes, and skills. Many of these ideas were picked up by Firaxis for XCOM 2 proper, which Pavonis helped provide mods for at launch.
I quite liked XCOM 2 despite numerous performance issues even on a beefy computer, and it’s been long enough that I’ll inevitably get sucked back in with this mod. According to the official XCOM site, we’ll know more in the coming weeks.