I'll be starting with the medium armors, since medium is your foundational armor, and working through the tiers before repeating this with the other kinds of armor. Granting access to it via equipment would be pretty bizarre to do -even when War of the Chosen does so, it harshlyВ limits it. Strictly speaking I could also comment on the lack of an armor for providing stealth, but XCOM 2's Concealment system pretty obviously replaces the prior game's stealth mechanics and stealth specialization has been made a class feature. Given this barely mattered even into Enemy Within, it's not a functionality that is missed, overall, even if it might've been a good thing for XCOM 2 to try to bring this back with a more meaningful execution. You have to turn to your Item slots if you want immunity to statuses and whatnot.

This is a good thing, as flight in the prior game was a godawful mechanic, and I'm not sure there'd be a way to keep it in recognizableВ form without overhauling the rest of the system or simply accepting that flight is a godawful mechanic in this system.ДЄlso true but not terribly important is that no armor provides anything equivalent to how Titan Armor provided immunity to fire and in Enemy Within Poison and strangulation. This is part of a broader trend, as what few enemies in XCOM 2 do fly behave radically differently and in particular are almost completely forbidden from hanging at arbitrary points in the air to acquire Aim boosts for most purposes, flying units are pretty similar to eg how SPARKs can jump atop buildings as far as travel ability. There's also no armor that provides flight. Also notable is that armor-provided HP is no longer treated as meaningfully distinct from innate soldier HP: a soldier who takes damage is going to need recovery time, period, and there's no mechanics equivalent to how Adaptive Bone Marrow couldn't undo damage to armor-derived HP. Where in the prior game high-tier armors provided Defense, no armor in XCOM 2 provides such: instead the light armors provide Dodge, the heavy armors provide Armor, and the medium armors ultimately provide some Armor as well. That said, there are some notable contrasts.

(Only Medium is represented at the bottom tier of armor) XCOM 2 is more explicitly organized along these categoricalВ lines, however, with all three types having a representative at the second and third tiers. Armor is broadly familiar to how it worked in the previous game, though the conceptual organization is different: where the previous game had Generic, Light, Flight, and Psi, XCOM 2 has Medium (Which is the default armor type), Light (Broadly similar to Light from the prior game), and Heavy, which doesn't really map to any of the armor types of the prior game.

War of the chosen armor