i like how this just mellows throughout...
and there is a good sense of judgement here,
with the synth pads for effect, being used very judiciously,
correctly,
good editing.
i still hear guitar all over this (of course!) LOL
it would have to be subtle to match everything else,
and not step on areas where you are introducing new elements,
because the keys and synths are stars here.
it would be very easy to tip the scale here,
to something that sounds more like 70's prog rock,
with the addition of guitars, drums/percussion, and a vocal
but totally works as is.
nice work.