EDIT: I thought I should use this opportunity to say that I am with GJ here. TA, IMHO, is a bunch of waffly mumbo-jumbo. That is to say, the only difference between quantitative methods and TA is the quality and rigor of the analysis, nothing more.
Out of interest, if you were developing a rule-based technical strategy* (or, say, someone approached you with one), at what point would you be satisfied that it was worth a pop?
And pursuant to your first point... I would agree that the rigor threshold for TA is... well non existent for the most part (if someone believes it, then it's legitimate TA apparently), but I would balance that with the point that most sensible proponents of TA consider it more qualitative information than quantitative, and treat it as such.
all IMHO.
* not stat/pure arb, HFT, but the type of strategy you read about here for example.