I'm not trying to dredge up the conversation on "who's more underappreciated: artists, or writers?" because that can be a one-upping nightmare, but one thing that I think can be talked about is the equivalent types of works between the two, and how they should be considered and regarded as much as their counterpart. I'm not saying they should be taken as strict clones of each other since it's still comparing apples and oranges, but maybe looking at them differently will inspire more/different appreciation than before.
Lots of people don't like the literary forms of them. In the published world people like them more, but I think that has a bit of a different frame than fanfiction WIPs (buying books in an unfinished series vs. a fic that is unfinished). One thing I saw someone say once is that an unfinished sketch is a lot like an unfinished fic, and that was the first thing that made me think about a lot of similarities between art and fic. I'm not an artist so I can't vouch for how it feels to have an in-progress sketch, but when I see artists post them to twitter/tumblr, I get a feeling that it's both similar and different from a fic WIP. Sometimes I can't tell if an art piece is unfinished or not, so I suppose lots of people are the same and get immense enjoyment from them, but they're still unfinished. I think that an unfinished sketch represents a different take on creation process from a fic WIP, too. I've never seen someone criticize an art piece for being unfinished, though, while I see that all the time for fics.
This is where everything turns to chickenscratch in my head. I can't wrap my mind around the fact that art can be unfinished yet still give people enjoyment as if it completes itself in its own way. This is probably because I'm not an artist, do not participate in that process of creation, and don't understand what goes into it. (Either way, though, I do love people's thoughts on their processes.)
Despite being a writer, I don't think even I completely know how I feel about my own WIPs. They're there, I come back to them when I want, and they'll always be there. Whereas unfinished art has its own quality that seems to complete itself to me, I think that fic composes itself in a way where each piece might be its own final product, and it's missing other pieces that make it whole. At least for me, whenever I upload a chapter, I do it with the intention that that chapter is finished and edited, and I don't worry about it anymore. I might return to it with extra touches after rereading it later, but the point is, it's finished. The rest of the fic is nonexistent, so in the context of pieces, it is not finished.
So when it comes to an "unfinished" work, I guess some of it comes down to how you value them and what side of them you value: an unwhole work with finished parts, or a whole work with all parts unfinished. (I'm writing this on the wing, by the way; I'm thinking on my fingertips).
We all know what redraws are: recreating a scene and reining it in under our own style. I've seen lots of artists redraw scenes, sometimes tweaking it to their liking. The fic version has no simple word to describe it, but it'd be something like this: re-depicting a scene, describing what you think is important, and tweaking it to your liking as well. I've read quite a bit of these fics, explorations on canon scenes, and I like them very much. Sometimes I think they can be considered character studies, depending on the situation. Maybe a scene has something that can be considered shippy, and a creator decides to bring that out. Or maybe someone sees an applicable side of magical realism to it. Either way, it's recreating a part of canon, and it's not tracing/copying every exact detail.
I don't really have much to say on this topic. I just wanted to bring these two similar phenomenons together because I think there's interesting consideration in understanding where they come from.
Ficlets and Doodles
I hesitate to say drabbles instead of ficlets because drabble has a strict definition of being exactly 100 words, and I respect that definition, but drabbles are also included under the subset of ficlets. For purpose of discussion, I consider ficlet as a fic that is considered small by the creator; as vague a definition as artists give to doodles. I once saw a tumblr post say that a doodle isn't necessarily a piece with minimal effort, but is something fun, indulgent, and takes little time to do (iirc; and op was an artist). So by categorizing an art piece as a doodle, an artist doesn't mean to degrade other artists by implying they can create "masterpieces" (in other creators' minds) with little effort, they simply mean it was fun and indulgent. Small. Relaxing.
I feel the same way with short fics. I really love them, and I don't necessarily think that there's less effort per unit time that goes into a ficlet as compared to when I write longer fics. Sometimes I plan out a plot for a longfic, do a lot of research, keep separate files of just notes and plot, etc., which is considerably more effort, but I don't that often.
Anyway, in my eyes, ficlets and doodles tend to revolve around one subject and make the focus almost completely about that. If a doodle is a picture of a sea, or a few plants, then I'd consider that an atmospheric piece. Same with a ficlet; if the focus is setting, then it's atmospheric. Here's what I love about fandom and fanworks: exclusively atmospheric works are an option! I think it'd be difficult to publish anything that is just about scenery and setting, but when it comes to fanworks, we know enough about characters that, even if it's not a character-driven work, the characters can serve as the background to atmosphere. This, I think, is what makes fandom perfect for dabbling in magic (in the literary sense!) and other fantastical settings.
If the focus is instead on a character(s), then the ficlet is character-driven and emphasizes something about them. I still consider that atmospheric sometimes, in a sense. If a character is taking a day off and is submerged in fluff, that strikes me as atmospheric. If there is a small plot (which is possible), then a condensed relay of events can happen. A doodle can be character-focused, too, and entirely on that character, with no background or plot (or if there is one, then it's usually a small plot point). Really, I think there is a lot that can be done with ficlets/doodles.
My point of all this is: there is no shame in doing the equivalent in one version of creation. If you're a writer, and you have WIPs, there is no shame in that; artists post their own versions of WIPs. You both did a lot of work, and you should be proud. If you're an artist, there is no shame in doodling pieces of characters in your spare time if it's what you love; lots of writers just do lots of ficlets of our favorite characters/ships, and even if it isn't obvious at a glance because it's impossible to enjoy fics at a glance (and also, looking at someone's ao3, I think, gives a different composite than the immediately available sensory information of a gallery of art on dA/tumblr), it does happen. And in general, if you're a writer/artist, there's no shame in treading boundaries of sketches/WIPs/lengths/effort/etc or doing something others might think is halfhearted.
And since I'm already on the topic of writers and artists, there is one more thing I'd like to add. I've seen lots of people say they wish they had as much support as artists, but one thing I saw an artist say that struck me was that they wished they had a branding and connection to their works and audiences that was more than a cursory glance. This artist felt that they couldn't really build something lasting to stick with people and linger in their heads when all it takes to enjoy art is a second of looking. Artists have the numbers, but not the depth; and writers have the depth, but not the numbers. So let this assure you that while there are things to be lost between mediums, there are also things to be gained.