Thiel Owners

Stereophile measurements actually indicate deeper bass extension with the 2.2 compared to the 3.7 (!), so your perception seems consistent with actual performance. Note that Tom Thiel still has 2.2s.

The 2.2 bass was our first passive radiator and as such it coupled to rooms better than anticipated and came out slightly under-damped and somewhat (1.5dB) higher in level below 200 Hz. It has the fullest bass of any Thiel product, which was warmly (ha ha) received by the public, but considered by Jim to be in error. Note the 1/3 octave Stereophile graph showing some excess bass. Notice also in the Stereophile review that the cabinet is possibly the quietest Thiel ever, including the new x.7s with curved panels. ( I have a fix for that 300 Hz and ringing, plus a hardening agent for the MDF baffle to increase rigidity. The 2.2 is the first (1990) cabinet designed from the ground up with in-house 5-axis CNC capability. I went wild with braces because they were so downright feasible! Note also the quality of the custom caps - those yellow styrene bypasses were from world-class German film / tin foil. The tweeter was our own from the ground up design for the CS5 - it is a powerhouse, even by today's standards. The woofer is the first iteration of the double cone with curved front and straight back. It is polypropylene with air core and works extremely well. That design became the basis for the present double aluminum with styrene fillet midranges. The most ordinary element is the midrange, but even that "paper" cone has polypropylene fiber reinforcement.

As you might guess, I don't feel the need to make many excuses for the 2.2. As Beetle mentioned, they are my workhorse which I use to critique recordings in the making.

Pops and others have expressed fondness for the pre-coax format. I agree that there is something simpler and cleaner in the wave launch. The coincident coax addresses a fundamental problem with first-order networks: vertical integration of the lobed radiation patterns. The coax solves it. But, IF you get your ear at the correct 35" up, the problem is solved at that listening position, obviating the need for the coax, which does introduce low-level anomalies of its own. The x.7 coax is better because the wavy surface spreads the tweeter-edge wave nicely.

Todd, you are not nuts. There are some significant strengths of the 2.2, and resolution is less in the the bass and midrange. The new caps and treatments will upgrade the overall performance considerably.

Beetle, the 3.7 XO pic you attached is for all 3 drivers. The mid and tweeter have separate motors (unlike the 2.4, etc.) with the midrange XO having the greatest part count (16 compared to 17 for woofer and tweeter combined).

I've got both the 3.7 and 2.2s and I've definitely noticed that the 2.2s have more prominent bass.  I'm not surprised to hear that they have a little more than is completely flat.  It's good quality and very enjoyable.  They were my first Thiels and I consider them to be pretty much perfect living room speakers.  They are so enjoyable, don't do anything wrong really.  I bought them used for a second system and they turned me into a Thiel guy.  They are an obscene bargain used.  For just sitting and listening to music at moderate volume and solely for enjoyment I don't think it gets that much better.  

@tmsrdg, It was a long time ago, but when I lived in NYC one my favorite dealers carried amongst others both Spectral and Thiel. They often rotated both in and out. I think this was up to the 2 2’s and 5’s time period, but pre co-ax. 
My recollection was that the combination demonstrated both of their attributes, but the Spectral while capable of handling the low impedance of say the CS 5’s, was happier with the above 4 Ohm and above Thiel’s.
 The Spectrals were admirably lighting fast, very detailed, smooth, with no electronic smear what so ever. Ultimately I found them a bit thin, threadbare and bleached. I can imagine them having their admirers though. 
 The Spectral’s were said to be rather particular about matching pre’s and speaker cables, with their own pre and MIT cables being very strongly recommended!
 Hope this helps.

Keep in mind when you compare the bass response of different speakers, it is hard to eliminate the room response of the different speakers. Several times I was ready to replace drivers of my 3.5 only to find out with near field measurement that the drivers were perfect but bass nodes and boundary effects caused the distortions. When I replaced the 3.5 with the 3.7, the room effects also changed significantly.