One question I carry along with me for a long time now is about being able to hear and sing everything you would play on your instrument.
Like you, I sing along to everything I play on the guitar. And it´s great because I really feel like my inner voice helps me to get deep into the music and creates musical ideas that seem to be much more natural than before. But at my stage it´s more like "I sing what I play" than "I play what I sing". Still I´m very much controlled by things that I have more in my fingers than in my ears.
So what I work on now is to synchronize my fingers with my ears.
Let´s say I improvise over a tune which I really have checked out and hear. And at first I improvise with my instrument, later just singing, without the guitar. In both situations I can be musical and create a more or less good solo. But if I record it and compare the two solos it´s really two different worlds. Just singing I sound much more "traditional", more controlled though. But I ask myself the question, how honest am I to myself when I play things that don´t come out of my inner voice, more out of trained finger mechanics?
I suppose it´s a thing you work on for your whole life, but your thoughts on this topic and ways you (and all the other members in this forum) worked on that issue would really interest me.