This was a big shock to read about
As I see it... Jim Thiel was one of a very few extremely big names in the area of loudspeaker theory and design. He had a very clear image of how a speaker should be, and for each iteration of a product he got closer and closer to his perfection. He always stick to his principles and never deviated from the base of phase coherence and impulse perfection. The latest CS3.7 must be a great example of this, being so good it obsoleted several of his upstream products.
Although, I never owned any Thiel speakers I very often ended up on his website to read about the theory and design properties behind his products. And always good reads around there!
A great master is gone, I hope his legacy will continue and products improve even further.
RIP Mr. Thiel