So here's the deal with gluten. It's the protein that binds the bread together. Gluten has to be "developed" which happens through kneading and rising. Having too wet or too dry dough will inhibit the process as well.
You should not have to add gluten unless you are using a GF flour (and usually people only use those because they can't eat gluten, and use stuff like xanthan gum or guar gum to hold it together instead.) If your dough is not rising enough or is too "tough" or too crumbly, you should consider your leavening amount or quality, how much you are kneading it, and for how long it is rising, and whether you have too much or too little water. I mean, you could add more gluten if you want, and there's nothing wrong with that, but it's not strictly necessary for any flour that naturally contains gluten, even if it's 100% whole wheat.
I make a simple whole wheat bread all the time. Flour, water, salt, leavening (Costco yeast ftw!), and fat. A sweetener like honey if I feel like it. I dump it all in, beat it to death in my stand mixer, cover it so it doesn't dry out, and let it rise for hours (punching it down every once in a while is nice too, if you're around). I have mixed it in the morning, and left it alone until before dinner, with fabulous, fluffy, non-crumbly results. It's not fru-fru but it's simple and hassle free, and, I think, quite mustachian. ;)
