I disagree. I like Thiel Speakers, and that "fundimental" flaw your talking about is becoming better.
The real issue with these speakers is POWER... and you need LOTS of it.
Second, your talking about a company that is reaching about 25 years old. They have just started to reach their prime, so I wouldnt disregard these speakers as beign poor.
Third, I enjoy the sound of Thiel... ALLOT... They are a bit reserved, and they are amazing at low volumes. They have been getting more and more praise with each revision. I expect the 3.7's to start beign some of the best speakers on the market. I wouldnt discount them, they have really progressed with each step.
Old Thiels are amazing, because their used price is VERY low. This is due to high power requirements, and that they were really high price / Quality when new. I would recommend to anyone to buy a pair of used Thiels.
3.6's dont share a low resell value, though its not as high as some other brands. When it comes to sound reproduction, NEVER count the Brits out until they are out.
Mike