I have no idea why, but suddenly I have noticed that my Moto G will now record in stereo using the "Titanium Recorder" (TR) app. The settings I am using are 48kHz sample rate, 128 Kbps MP3 Stereo, which may be the format that the phone uses to record audio for video clips.
When I last tested the Moto G's capabilities, it seemed only the camera's video sound track could be recorded in stereo; all other apps I tried (6+) could only record in mono, regardless of the settings.
A previous strange experience involved the use of the ASR recorder, where the default settings (66 Kbps Ogg Stereo) allowed me to record one file in stereo. After changing settings in ASR, subsequent files all came out in mono regardless of settings (can't imagine why).
Anyway, I have rebooted the phone since, and TR still is able to record in stereo. However, I am afraid to change any TR settings for fear of the same thing happening with TR as did with ASR.
Fortunately, given the hardware (limitations of mics, etc.), being able to record in 128 Kbps Stereo MP3 is acceptable to me; recording my piano playing came out pretty well, with no noticeable Automatic Gain Control distortions.
Don't know if this has anything to do with the KK 4.4.3 update; it's certainly not mentioned anywhere by Motorola.