I'm glad your focusing on the single player aspect, I like the idea. I think the vision of the game experience you have is beautiful in and of itself, I don't believe MP would add much either.
I'm fascinated by Starfarer, it's a gem of a title. This has 90's era game quality written all over it, from a time and age when games were more intimate and personal.
Syndicate, X-Com, Master of Orion, and a few other unique games that were crafted so powerfully. They would immerse you in a beautiful little sandbox and let you lose yourself for hours on end in some one else dreams of an alternate reality. MP would destroy immersion or suspense of disbelief.
So far I am blown away by the quality and attention to detail of the well thought out game mechanics. I am very interested to see the end result.
Just my 2 cents