: I don't remember her introduction, but she was injured during the Mayhem's
: crash. The Huragok that the Elites brought with them fixed her up, and
: when one of the Spartan IVs came to visit her, she accidentally knocked
: him to the ground. That got people speculating that the Huragok had
: somehow augmented her while doing repairs, until they remembered that this
: is a Spartan IV we're talking about.

Actually, I don't think she's an S-IV at this point yet. So she just knocked that S-IV out because she's that good. Because the author said so.

: -The description of the monster-that-was-once-a-man didn't feel like
: something out of Halo. It felt like a description of a cheesy
: monster-of-the-week from Dr. Who.

This was extremely grating for me. The cyber dude was purposefully written to be a grotesque "science has gone too far" archetype and not something a Forerunner entity with Forerunner medical tech at its disposal would plausibly create.

: The end result: We're told that she's a top tier martial artist and a master
: linguist and an expert on Sangheili culture, but the only payoff is a
: dollop of romantic teasing with Usze 'Taham. Seeing as how she and Buck
: are the only interesting members of Osiris, she deserves better than that.

To be honest, as far as Osiris goes, I actually like Tanaka more than Vale. The idea behind Vale is interesting and unique but the execution ends up making her look like something out of a cartoon (that applies to both her character design and characterization). I won't call her a Mary Sue since that term tends to get abused a lot (and by the commonly accepted definition it only applies to fanfics anyway), but I will say she has a lot of traits of a Mary Sue.

At least Tanaka comes across more like a person that might actually exist, her backstory involves having to work and overcome obstacles to become a badass, and even then her skillset isn't as arbitrary as Vale's. Sure, her inclusion in Osiris is pretty random and she came out of nowhere, but there's something I like about her. Maybe it's just because I often tend to root for characters who don't get as much hype.