Does playing video games increase attention and learning agility, therefore career performance
I think your references are good examples of the way that some of this research is covered in the media (World of Warcraft is good for you! Yay!) as opposed to the academic research which is much more cautious and limited. You seem to be familiar with the 10+ years of research by Bavelier, Green and colleagues showing improvements in attention. The first part of your title/question ("Does playing video games increase attention and learning agility?") is well discussed by those papers, and also by this SE answer. My take on it is that there remains some controversy, particularly about whether games (and it is normally action video games they are talking about) actually CAUSE improvements, and the degree to which that transfers to more general tasks.

The second part of your question (does playing games enhance your career performance) is always going to depend a lot on what careers you are talking about. I wouldn't read too much into the McKinley and Rosser papers which you cite, as they both seem to look at highly specific "simulation-like" careers (drone pilot and endoscopic surgery), and I don't find it hugely surprising that skills from gaming transfer there. I'm also not sure of the definition of "learning agility" which seems a bit vague, and would want to see the evidence that "computer programmer at google" requires particular skill X. Why does it "feel very uncomfortable to make the conscious decision to play video games, in order to boost career performance"? Perhaps it is because such gaming takes time (indeed the amount that some spend is astounding), and that is time that could instead be spent on other sorts of more conventional education and training. 

So my short answer to your last question is that those studies are not valid for endorsing gaming to boost general career performance, and that you should seek specific training for whatever career you want (be it something game-like or not).