I like what you are going for and I think you are almost there. Start with the bass. I think, just maybe, in your zeal to make something interesting with this instrument that you don't play you are doing too much with it. The part you've written may be cool on its own and fun to play, but the song is suffering for it. The song itself is good, the cadences of the changes are great. I'm not sure it needs to have the bass so busy in order to be interesting. That back and forth whole step riff, for example, kind of distracts me. That may have something to do with you not being familiar with playing the instrument; you do sound like a guitar player playing a bass.
Think less of "riffing" and more of using this instrument to anchor the song. My opinion is that the song wants the bass in particular to probably be doing something more boring: more along the lines of what the rhythm guitar is doing and in lock step with the drums. If you are going to have the bass riff out a little, then I would say use it sparingly at transitional points of the song or where there are drum fills. I also think the synths could be reined in some way and given a part that is more predictable and then only really let lose at specific points. And I would plan the solos.
This may sound far more boring than what you envisioned but I think it would tighten it up a good deal and make the instruments really stand out when they do do something interesting. I do think this kind of genre benefits greatly from tightly organized parts. It's not the type of music that works well in Jam format and it sounds like a recording of a Jam.
The bottom line is that you've got a good song structure, you've recorded the sounds well, you've got a decent mix, now make it more than just a jam. Some of the specifics of the performance parts sound winged like the Grateful dead, so it doesn't surprise me when you say they are. I love the dead, but I don't want to hear the them play Joy Division. lol. I realize that following this advice means perhaps sacrificing something you envisioned and undergoing another recording ordeal, so just consider it. I am far from a song-writing guru, much less, a recording God. It's just what my ears are telling me after almost 25 years of playing guitar. But, I could be wrong, and I don't want to be responsible for it if I am!
