TL;DR
Wow, that is heavy. The first issue I see is that people only read the first part and think subs are evil because of the nice phrasing that make it seem like subs are forcing you to be or do something. They don’t read the second part where friday states that one needs to build a solid foundation.
Quite frankly, there is a reason why it’s a multi-stage, a reason why Saint’s message from release was to take time on each stage. In some cases our recommendations were to start out with healing subs or subs like Ascension or Primal first. As Boromir stated, one does not simply jump to stage 4 of a multi-stage. We won’t stop you, but we advise against it (maybe that’s why recent multi-stage subs contain stage 1 in stage 4, because nobody listens to us).
I personally think it might be possible to have a subliminal where the script describes things so alien to the listener that their mind simply doesn’t understand the concept and ignores the entire thing. I have warned people about this multiple times on this forum. There’s no harm in it, the worst thing that can happen is nothing. You listen for months and end up with nothing happening because its ideas are too unfamiliar.
Khan can be run as a user’s first sub, provided they stay on every stage long enough before ending on stage 4. And take action to support those ideas, even if it is reading up on them at first.
Also consider that subs are a lifelong journey. I mean, if a sub contains scripts that make us challenge ourselves, remove all our limitations, make us smarter than any man alive and turn us into the alpha of alphas, the king of kings, emperor of all men… then where are these gods among men? Certainly after years of exposure we should have at least one demi-god walking around?
Fact is, even if the subs do these things, it is a gradual process. It will accelerate over time as you release more and more of your preconceived notions and limitations (look at how far Saint and Fire have come in a matter of years), but you’ll still have to walk before you can run, and run before you can sprint.
You can run Khan for a decade and still not command a horde of followers or have had sex with every celebrity on your bucket list, but you will be able to look back and see how much you’ve changed (y’all are keeping and saving journals, right?). Even after that decade, Khan is still giving you new ideas, new directions. Because your ideas of what is possible evolve with you. Khan had to make you realize it was possible before it could help you achieve it.
The subs will shoot for the stars. Maybe you’ll end up on Mars instead. Still further than any other has gone before. You can look back at a wildly successful and satisfying life and legacy, knowing you did well even if you didn’t become Emperor of Man.
What were we talking about? 
In short:
In my opinion it is possible to run a sub that is too complex to handle. That sub would then do either nothing or work incredibly slow as it has to achieve a million minor shifts in your thinking first before it can fulfill its purpose (it’s one of the purposes of the core script in every sub).
There is no harm in doing so, but there’s probably a better sub, a better path for you to take which would help you achieve the results you seek faster. Why else would we have so many subs doing similar things in different ways?
So no matter how powerful Q+ might be, if it describes quantum physics to a toddler it’s still not going to work and the odds of it not working at all are even greater because the sub is so much more powerful. Once subs can work without using actual words, we can talk again.