Yeah, DD is like this. She has been reading fluently for a long time now, but her writing is far, far behind in comparison. She first wrote her name, recognizably, at 2, but she doesn't practice much. Every once in a while, she gets on an I-want-to-learn-to-write kick, and then she'll practice a lot, and makes significant improvements...and then she stops for a while and seems to forget all about it.
A few things we do:
When I'm writing something, she will help by writing some of the words or some of the letters. For example, when we recently moved, I labeled each box on each side (I know, I'm a bit of a nut). She would watch me write it on the first one or two sides and then want to do it herself on the other sides.
We make cards to send to people. She does the picture, and then we compromise on who does what writing. I typically write a bit of it and she writes a bit of it.
DH & I often sign our artwork. So she sometimes wants to sign hers. That gives her a bit of practice, especially because she sometimes wants to write her (long) full name.
DD has workbooks, but she doesn't use them much. She also has a few of the dry-erase books with letters to trace, but they're really frustrating because the pen slips around so much that it is impossible (even for me) to make one's letters really neat. I do think that tracing can be a helpful tool in learning to write, but I don't think it's the only way to do it. DD mostly prefers to watch someone write a letter, then write it herself.
Recently, DD got the idea that she wants to make her own book, but we haven't had time to do that yet. Maybe today.

I'm not worried about her learning to write, but I guess I might be more concerned if she was in school. She's probably just a bit ahead of average, but that would definitely hold her back if we were going to have to try to advocate for the radical acceleration she'd need to be challenged in a school setting.