stuuuuuffff....
Wow, um, that's a lot of words.
You seem to be arguing that Dual Natured is some sorta crippling disadvantage. I see some disagreement on whether it is, on balance, a slightly good thing or slightly bad thing, but I don't see anyone else agreeing with you that it is some sort of huge disadvantage that more than makes up for regeneration, various stat buffs, etc.
Guess I'll be the first.
Let's go ahead and look at what Dual Natured does.
A dual natured creature is active in both the astral and the physical at the same time. They're capable of perceiving and interacting with both worlds at once, and do not take the -2 penalty a normal mundane takes for being active on both.
So, compared to a dude who's assensing, Dual Natured gives you +2 dice to actions on the physical plane.
On the other hand, the dude who's assensing can turn it off. As it happens, this is a pretty big deal. First, it's rare that one will be forced to assense and perform actions on the physical plane at the same time, particularly in an instance where the assensing is not being used to get around a worse penalty (such as assensing in a pitch-black room to take a -2 in combat rather than the -6 or -10 from darkness and other possible factors.) This degrades the positive value of Dual Natured greatly, making it very, very niche.
Unfortunately, that's all the positives Dual Natured has going for it. What are it's downsides for an intrepid shadowrunner?
Well, first, you stand out in a crowd. Even a watcher construct will casually and easily pick you out from a crowd. Random spirits or assensing mages will pick you out similarly, automatically tagging you for extra scrutiny from security as someone who is definitely magical. This is pretty bad in and of itself, but the fun's just getting started.
Second, you're vulnerable to attack. The same entities who are capable of spotting you out from a crowd are also going to be able to send assault after you - assault you'll frequently be able to do nothing about. Sure, you can train Astral Combat, if you have the willpower and charisma necessary, or you can even forego that and use your natural weapons. However, astral combat has a critical downside, and you as a meat-creature have another. Astral combat is melee only. You can only move as fast as your agility allows you to. Any astral being is going to be capable of performing hit and run attacks on you using astral combat that you'll barely be able to react to, assuming they don't one-shot you before you have a chance. This is entirely discounting the possibility of a hostile magician or spirit of man simply flying above you, out of reach, and plinking a few manabolts at you until you die. A force 5 manabolt can keep 5 hits - far more than anyone can reliably keep - and inflicts only 2 drain on the caster - low enough to be trivial - meaning that the eventual weight of odds means you'll die, and the mage might have a box or two of stun for their troubles.
That's not the worst bit, though. "But Voro, that can literally kill me with me unable to act in response, how does it get worse?"
The worst bit is dealing with mana barriers. Unlike a mage with foci or sustained spells, you're always active on the astral, so you'll typically have an opportunity to spot them before they run into you (though not always - elevators, cars, and other things that can trip up even an alert mage can trip you up in the same way.) On the other hand, the stakes are much higher. If unnoticed - like one placed over an elevator shaft, or across a roadway or other path for motor vehicles - a mana barrier will roll opposed rolls against anything active on the astral, with the loser (or tied party) in each roll being turned off - and the creator of the barrier being informed of the intrusion. For active foci, turning them back on is a simple action. Trivial, though still a hassle in that it alerts security, albeit with a delay for the mage to send the comm message to the right place and all that. For sustained spells, it's more of a hassle. You have to recast, hope you get as many hits as you wanted, and suffer drain again... and if you used background counts or reagents to your favor for your limit, you'll have to spend more reagents to get it going again.
Unfortunately, when a dual natured creature is turned off, well, that's a bit harder to fix, since their stun track is filled and they're knocked unconscious. Even if this isn't direct cause to abort the mission, it's a terrible inconvenience, possibly a lethal one.
How do you avoid doing this? It's simple. Stop in front of the barrier (if that's even possible) and try to slowly ease your way through, making a Magic + Charisma [Astral] test opposed by (Force of the Barrier * 2).
Simple, but not easy. Even casually guarded facilities will have a force 6 barrier, with secure facilities easily reaching 8, 10, 12, 14, or even higher over sensitive areas. If you didn't select a magic priority, you have almost no magic, and if you're not using Charisma for anything else, that's likely low too, so even a force 4 barrier will give you difficulties, much less anything seriously employed by security. Even if you're a charisma tradition mage, you're chucking 12-16 dice
at most, and if your GM is particularly strict on the interpretation, a failure will force an intersection and risk unconsciousness.
Now, remember that most buildings in the 6th world will have some kind of astral security, which will likely involve at least a low-to-mid force ward over
at the very least the back room and secure areas, and you can see where the day-to-day life for an intrepid criminal who is dual natured might be difficult at best.
tl;dr - if people don't think Dual Natured is a big negative, they don't understand Dual Natured