It needs to sit and marinate for a while, and I will have to return to it with fresh eyes.
I tried to identify to myself the difficulties I experienced with this story. I thought I'll be able to explain them in a few simple sentences. Once I started putting them on paper, the few sentences ballooned into a long essay. But the final week of the year is an appropriate time for long essays on things I've learned this year, is it not? Thus, I'll present my musings in installments over the next few days.
Problem 1. Protagonists without outward characteristics are boring.
It is hard (for me, anyway) to write a story with characters that don't exist in human flesh. (I'm speaking about my most recent, not-quite-finished story, but the problems I'll describe here are specific not just to this story, but also to almost all story ideas I have in mind. They preclude those ideas from turning into finished work.)
The characters of my most recent story used to be humans, but their personalities have long ago been digitized and encoded onto rays of elementary particles. They still have ties to the humanity, though -- in fact, they are working in service of humanity. They are hurtling at light speed across the universe on a mission directed by a human government. So they are not total strangers to humanity, far from it.
Regardless, the physical reality surrounding them is nothing like ours. They don't have anything like our senses, perceptions or body language. So I can't describe their interactions among themselves, and with the environment, in the usual way one would describe human interactions. For example, the whole aspect of appearance and body language is lost. I can't add depth to the characters by describing their clothes or their posture or bearing. Rays of particles don't wear clothes, they can't shrug their shoulders or smile. ;-) I can't even use expressions like "he saw" or "she heard", because their perceptions of the world -- the information they get from cosmic radiation and the like -- are nothing like hearing or seeing.
In a word, when you remove all the outer human characteristics, it's hard to keep these protagonists from coming out very one-dimensional, and their conversations rather dry and flat. This has made me doubt whether this story was viable at all. That's why I'm letting it marinate, on paper and in my head.
There is a real dilemma here. If you want your story to be set in a distant future, it would be silly if your protagonists looked and acted and had similar mannerisms as the 21st century people. It would be even sillier if we created far-future humans by taking our contemporaries and decorating them with superficial "futuristic" high-tech and body-mod bling. I've seen this done in science fiction, and those characters inevitably came out looking like a little more radical version of a 21st century pagan-bisexual-pierced-tattooed-burning-man-going urban hipster. That's not at all what I wanted for my characters. So it would seem wise to give up any pretenses at being able to extrapolate their outward appearance, and forego the appearance entirely, focusing only on their thoughts and dialog. But that leads to protagonists being rather flat and boring.
That's one aspect of the difficulty I'm having. I'll talk about another aspect in the next installment.