Actually Reach described it fairly well. They're SIIIs, and this particular group is a very special group that has managed to cobble together different pieces of armor and items to perform the special functions that they need to perform. They're supposed to be unique in this ability.

Halo 4 basically continues the idea that Reach was special, give or take. The SIVs all seem to have like-armor, give or take helmets or a few other things (at least until you get into multiplayer). Time has passed, so even if H4 went with a Reach-like approach, it could be because they found it more useful. Same for H5.

The notion that in H2, though, that Linda would have that different armor, well, that doesn't fit with pre-established story guidelines to this point. And as others have pointed out, that helmet is damn ugly, and 343 is basically treating their audience like complete idiots. That is what it is, I suppose. At least the Terminals as a whole were pretty well done.

: Also really goofy since this is H2 and they should be in Mark V anyhow. I
: assume that their assets were based on something in-game in the future,
: however :)

And that. But asking me to trust that 343 knows their shit at this point is like asking me to trust 343 to make a good game on their own. Until I see it with H5, they get no credit for all the outsourcing they've done with MCC. They will get a ton of my appreciation and gratitude for making MCC a thing that actually happened, but that's it. Certain Affinity though, man, I hope they get one nice, huge, freaking fat and ridiculous check and bonuses for all of their excellent work.