I think part of the problem is it didn't have any fanfare surrounding it's release. I did not even know the phone was out until I went to look for a phone to get on Sprint.
However HTC is discontinuing a lot of phones this year, including the original EVO 4G which is already discontinued/EOL. Hopefully fans of the EVO line will move up to the Design and we will get more devs working on our phone. I really hope that they find a way to get S-Off for our phone so we can flash recovery and ROMs without unlocking the bootloader when some become available.
Samsung Galaxy S® 4 MJA Rooted with CF Auto-Root Tutorial
HTC EVO Design 4G™ v4.0.3 Bootloader Unlocked & Rooted with HTC SuperTool v3
If it ain't broke, use a sledge hammer.