Generally, the Edgerunner Perk allows you to push your body past its reasonable limits by installing more Cyberware than you probably should. Along with being able to enjoy more (and more powerful) Cyberware, this Perk will also occasionally grant you an absurd damage bonus that allows you to instantly kill most things in your way. The downside is that you sacrifice more maximum health the further you push your character past their pre-determined Cyberware limit.
That being the case, you may be wondering why you would want to focus on melee and close-range attacks for a build that has to sacrifice max health. Well, there are two main reasons.
The first is Gorilla Arms: the heart of this build. With the right combination of Perks, you can turn Gorilla Arms into arguably the most powerful melee damage option in the game. Most of your Gorilla Arms strikes will turn enemies into piles of goo, which is obviously an ideal outcome for any blunt melee strategy. However, Gorilla Arms also boast incredible Shockwave AoE stun abilities (especially once you unlock Relics), and allow you to actually throw enemies at other enemies for devastating damage bonuses. Of course, picking up Gorilla Arms and building around it means that you’re inherently “spending” quite a few Cyberware points. At the very least, Edgerunner allows you to make up for those spent points.
That’s the other big benefit of picking up Edgerunner with a melee-focused build. The biggest downside to Edgerunner is losing your Max Health, and one of the best ways to gain additional health benefits is to invest in the Body tree. Well, the Body tree also happens to contain some incredible melee abilities. The synergy between Edgerunner, Body, and strong close-range/melee attacks is just too good to pass up. Investing heavily in Body means that you can pick up all that extra Cyberware without needing to ensure that all of that extra Cyberware is just there to compensate for taking Edgerunner in the first place.
Admittedly, going that route does make the rest of this build slightly awkward. For instance, you’ll notice that I invested quite a few points into the Cool tree without actually taking any Perks in it. Well, that’s because I’m opting to go with Shotgun-based Perks instead of picking up Pistol Perks. That’s largely because it’s easier to use Shotguns in the close ranges that we’ll regularly be operating in. If, however, you’d rather have additional ranged options, then I do think that picking up Pistol Perks is your best bet (which is why those extra points are going into Cool in the first place).
I suppose you could also remove some Perk points from the left side of the Technical Ability tree, but I wouldn’t advise sacrificing that part of the build. Not only do you get some fantastic Health item buffs from that section, but the amount of Cyberware you’ll be taking basically turns Ticking Time Bomb into a nuclear weapon.