No, I don't think that at all.
Even if you use your TA to give a price range and corresponding probabilities I still think it's no better than random unless you can statistically prove that its not.
I get where you're coming from. "If it works, it should be possible to _show_ that it works." (where "show" means something like "up to current academic publication standards"). Did I get that right?
Let me make a countering case. I suggested the analogy before in some other thread, so apologies for the repetition:
Imgagine you're a computer scientist in the 1970s. You implemented a computer chess algorithm on the fastest then-available machine, nothing more complicated than alpha-beta pruning (or variations of it). You still fail to beat a competent human GM. Consistently.
So, you ask the GM how he plays chess. He'll throw an entire library of opening theory (or endgame theory, or whatever) at you. You read it, and will quickly realize that this completely
unimplementable. Worthless, from your perspective. Yet, still, that GM beats your machine nearly every single time.
End of analogy. In my opinion, TA as she is practiced by the more competent traders in here, is as much of an art as it is a science (thanks to sgbett for that phrasing).
It's difficult (though not impossible) to show that it produces statistically significant results. And even then, what is tested is only a tiny subset of what traders actually use for the TA: the purely algorithmic part, while in reality the algorithmic methods go hand in hand with intuition/human-optimized pattern recognition/etc. (like in the chess analogy above).
It really runs down to the following question, in my opinion: do you
only accept knowledge and results that are produced by the full rigor of academic methodology, or do you allow for "conditional knowledge"... insights that appear reasonable to you, that you have personal annecdotal evidence for, and that you hope can eventually be proven to be correct in a more formal way.
Myself, I follow the latter approach: I believe I have tentative evidence that TA (as I practice it) works well enough, but I don't expect to be able to show beyond a doubt that it does work, because (as you already pointed out) the system underlying it is too complex (and not well enough understood yet) to formalize it to the point where the question can really be answered once and for all. Until then, I will continue using those methods, with tight risk control in place to avoid catastrophic failure should the methods "stop working" for me.