Interesting spin on events.
It is not a spin. The xmegas were announced in February 2008 as immediate available, but you couldn't get one. In the same year Atmel bought themselves some awards for the non-existing MCU, the EDN China Innovation Award and the 2008 Product of the Year Award by Electronic Products Magazine. Mind you, for an MCU no one could get.
In 2009 Atmel showed some eval board, which you couldn't get then. Not for love or money.
In 2010, two years after the immediate available announcement you could occasionally get an engineering sample. Around 2011, maybe late 2010 you could buy the dreadful rev G silicon and a little bit later the still very much broken rev H silicon.
In the meantime announced xmegas just silently disappeared. E.g. the A1 family was announced containing not only the 128A1 and 64A1, but also 192A1, 256A1 and 384A1. So in theory you could start with the 128A1 and later on in your project do some rightsizing. In practice the 64A1 appeared very late, and the others never materialized. The D4 (or was it D3?) series had a similar faith.
People were not just confused about the ADC or other new periphery. The errata, after Atmel finally came clean, listed some really horrible things. The ADC broken, the DAC broken (just something like 200 LSB off in some mode ...), the BOD self-enabling and locking you out of the chip in some cases, I2C timing broken, part of the clock system broken. And a few nastinesses that never made it into the errata, but were present. Like Atmel couldn't be bothered to perform the specified factory calibration.
A lot of what made these new MCUs interesting was broken. And that after people waited more than two years to finally get some. Oh, also famous on some series was the error that you couldn't write to the EEPROM without completely holding the MCU clock.
And that joke of a library was indeed called ASF. You could spend a lot of time debugging the library. It was as if the ones writing the library had no access to the real silicon and never tested their code. But Atmel was pushing the library very hard. And you could only use it with Atmel's horror IDE. The IDE that refused to install, refused to start, refused to properly communicate with its own debugging backend and refused to work with Atmel's very own programmers. Not to mention that Atmel promised a cross-platform development environment and instead delivered a Windows-only PoS.
The xmegas were shitty to work with, and for a long time Atmel denied there were problems. It was Atmel's behavior that finally broke the camel's back. Just too many broken promises.