Although really well done, as in sounding very professional and mixed together perfectly, I think it was missing a certain layer of depth. At around 2:45 this is fixed a little bit, when the high pitched sound comes in. The more bass sounds needed to come out a little bit more too. And despite it being an ambient track, I think it needed a certain level of growth throughout the song. You can notice this by jumping at 30s intervals. Once you get past the halfway point of the song this starts to come in, but I think if it was stronger, it would be a much better way to progress throughout the song. Regardless, don't take this as this isn't great work. Keep this up, and you'll be fine.

I think a helpful hint, what is key to ambient/drone, is spatial imaging. The drone pads appear to me L/R panned extreme (which is fine), whereas most other elements are pretty center strong. If you want to do this route, I'd say take a center fixed element, and send its reverb aux track elsewhere so it isn't FMP'd. This could create a wider sound, but still be experimental. Another possible idea is employ some Haas effects; have a "lead" (I know its drone, so there isn't much in melody/leads) sound be left or right of center, and double the track; set a delay on the second track with a delay >30ms, depending on tempo of the track. Color it if you desire/can, and also attenuate the delayed track slightly. This produces a huge wall of sound often.

Those are some possible ideas you could incorporate to give it a deeper sense, in my opinion.