The build I'm doing is working pretty well on very hard. I'm up at lvl18 reflexes and lvl14 cool. Really gotta almost max reflexes first. Top far left perks give massive damage boost for 100% health enemies (which they all will be) while the one below it gives increasing damage for each bit of health missing (finish off on the second swing.) What you get with the Blades tree really has all that's needed to survive. I didn't spec into any of the bleed stuff - if they live long enough to bleed, they will kill me. Obviously no counter either. I'm not leaving time for counters/dodges or I'm getting shot up from somewhere else and those buffs aren't saving me with nothing in body. All of my armor rating comes from cyberware and regular clothes. No defense buffs or stat boosts to be had, other than the movement defense boost, which... better keep moving or die fast. Right now my base defense is only ~450 with only 225Hp at level 21. But it's fine - enough to take a big knock or two is all I need and it's not like I'm easy to hit. Far right heals 20% for each kill, which is huge when you're chaining kills constantly. Again, later perks are most important. The attribute bonuses are good, too - make enemies miss more and solid crit chance bonuses. Glass cannon, essentially. Though Sandevistan is a lifesaver. I use that if I'm just getting fucked. Actually doesn't happen often, though. I can always drop away for a few seconds and let regen kick in. It's a finger snap to get back to the action with the mantis blades.
Cool, I generally don't use for stealth. The attribute boost does come in handy though. Crit damage and resistances boosts from cool itself. Very useful when you're getting in the fray. Stealth tree only has two perks that I think are worth it. From the shadows gives a 7 second, 50% crit boost starting combat. Hasty retreat gives a 50% speed boost for 5 seconds upon detection. But I'm not using it to run away... lets just say I want em to see me coming.
Cold Blood is what really makes it interesting. Between three perks, you get 5 guaranteed stacks that trigger for each kill, granting speed boosts. Another adds a chance for a stack for each crit... and nearly every kill is so those are good odds of landing two stacks on an early kill in the chain. But on top of that, you can get a 20 fuckin percent armor boost for each stack. 4 more levels and I can add 5% damage reductions. 30% movement boost. 10% melee boost. 100% health regen boost. PER STACK. It gets crazy really fast. You've got multipliers stacking on percentages pushing those stats wayyy up very quickly. In seconds, you become a crowd control machine. DPS out the yiz, landing crits the majority of the time which aren't only keeping you alive, but making you fucking stronger. It's kind of nuts.
Haven't even gotten much into the cyberware, yet. Got double jump, and legendary subdermal armor can be bought really early. Mantis blades don't need to be bought or acquired from a quest, and that's all I'll say.
Really, those three things go very far towards literally flying around fucking everything up from basically the start of the game if you go right for em. There are plenty of other useful little boosts to be had through body mods though. Some of the good ones require some investments in other atties. Might do that later. I could have reflexes and cool maxed by the 30's, which leaves me free to boost whatever suits me.
I am totally giving up on hacking here, though. Kind of a big decision. You can totally stealth without it. Moderate cool attribute boosts see to it, but you're really gonna be Solid Snakin it. It's a challenge. I really do find it's optional. You have what you need for missions and getting around. There is ALWAYS another way. You lose cash from jacking in, but gain it in selling loot, since there's little reason to break it down. I don't waste no time running this build. Half of the time 3 of of them are dead before they realize we're fighting
And by then, it's too late for the 7 others. You lose your stacks after 10 seconds, which is PLENTY of time. Be adding another perk that makes them drop one by one instead of all at once in two levels.
It's a fair trade, I think. But you really gotta be fast and execute when in combat. No sizing shit up. See a guy, get there fast and kill him. Go to the next closest, and the next closest. It's okay to have a couple far off - they can't really hit you much and when they do it often knocks of 1 fuckin hit point. Not to mention with movement boosts you can be on em fast, even using katana's, which I still use sometimes because they're more satisfying to hit with.