I haven't been partaking in this discussion very much up to now. As a classic "mixed signal" guy, I've been deeply disappointed to see that the T4.0 wouldn't have any DAC outputs. After the T3.1/2 with one, the T3.5/6 with two, I had secretly expected to see at least four of these on a newer and more powerful MCU. A higher bit depth for the ADCs and DACs would have been a "nice to have", too. I'm perhaps late with everything, but I started only a few years ago to think about re-creating all that pure analog and sometimes discrete CMOS stuff which I had created in the audio and music domain until 2013 on a mixed signal MCU, where the Teensy product line appeared the most appealing to me. My (naive) idea was to have really everything in one.single.chip.
Now, after having swallowed my disappointment and after having seen that it's not only PJRC or NXP, but that other manufacturers like Cypress, Ti, and Analog Devices(!) don't go the mixed signal way I had wished either, and that for example simple and nice components like the I2C audio volume controllers/drivers from Princeton Technology have become rapidly obsolete, too, I'm forced to re-think and to retry things again and in a still more digital way than I initially intended.
Thus, please don't take my temporary silence here as a disapproval of whatever happens actually, it's just that I felt somewhat left behind by the actual technical evolution and I'll need most probably still a little time to catch up.