I am considering a 1 year visiting assistant professor position so as to have employment upon my defense in the next few months. However, after that time I would seriously consider other options including postdoc positions, but I wonder how difficult this 1 year "gap" would make obtaining a postdoc position. I would still be able to collaborate with the research group I am currently in and would also look to develop some theoretical/computational aspects of my research abilities during this time. I also have a paper to be published likely after my defense. Looking for any insight or if anyone else has been through this same situation.
If the alternative is a gap year then it is a good idea to take it or, at least, consider it.
Presumably a visiting assistant professor, if you don't hold an academic position elsewhere, is just about the same as a post-doc but under a different name, since it isn't tenure-track. It would, of course, depend on what is expected of you.
If the duties are very heavy on teaching, then it is more like a better paid adjunct. You probably want to avoid that. If it is similar to an ordinary faculty position, with some teaching and some research then it can have long term advantages for an academic career. But consider, also, what courses you would have to teach and how much support you get in doing that. And, some post-docs do teach.
If you are doing research (successfully) during this year as a non-student, you have the opportunity to change the relationship you have with the faculty, building up a circle of collaboration that can be advantageous for your career.
Overall, though, I'd think that it gives you more, not fewer, options. And certainly more options than being unemployed for a year. But if this is the first option that pops up, don't neglect to look for others before you commit.