After 2 1/2 years of ownership, I don't get overly concerned about things like that simply for the fact that the Spark is doing what I expected of it. I can commute with it and I can do all of my local running around with it.
Congrats on your Spark purchase. I picked up my 2015 in November of 2018 and since then, I recently replaced the 6 year old battery and the 6 year old rear tires. That's all the maintenance I've put into it, so far.
Weber Auto looked into adding DC charging to a Bolt that didn't have it and found it couldn't be done. I would imagine since it's similar in layout to the Bolt, the Spark is in the same situation. https://www.youtube.com/c/WeberAuto/videos