Apperently there has been an official GhostBSD release with just a window manager in the past. However that was quite some years ago (GhostBSD 3.5 era!) and the wm was Openbox. As far as I know it was dropped because maintaining too many flavors was simply too much work.
In general there's nothing wrong with just installing x11-wm/awesome
on top of any GhostBSD installation. In fact that's what I'd recommend you to do and see if it works for you. I've just checked it for you: You can install it using OctoPkg or pkg and it comes with a session file that Slim recognizes. When you start your machine and the display manager comes up, use F1 to cycle through the available sessions before you type in your username and password. Awesome should be available there. I'm not familiar with it nor confortable with LUA. So I've just made sure that it can be started and would like to leave the rest to you for now.
If you try it please report back here what works and where there are problems.
But as you suggest using just a WM I assume that this is probably not what you want. I have a soft spot for minimalism myself (I've used ultra light-weight solutions myself for years) and thus guess that you actually want a small system with Awesome but without the bloat of a full DE that you don't want to use anyway, right? In that case you can of course go ahead and start removing packages. Still that's not the cleanest solution and I'd not be really happy with it, too.
I'm all for the idea of tiling wms (even though I never found the time to practise their proper usage). Here's my suggestion: I'll be working on the documentation side of GhostBSD and I've planned to get a bit into the build infrastructure anyways. One of the things that I want to give a shot is modifying the "mini" mkscript to allow people to roll custom spins of GhostBSD. I could really have chosen just any example - and I might simply opt for Awesome in this case. Only condition: You write a short intro about the basics of using that WM (I don't currently have the time to do proper research to learn a new WM myself)! Deal?
Oh, and once I have the unofficial Awesome image ready, I'd of course share it so you wouldn't have to build it yourself. I cannot promise you an official Awesome-WM spin of GhostBSD but that way building GhostBSD with Awesome would be part of the documentation. If the others agree (and I don't see why they wouldn't) your intro can be put into the wiki as well.
Once you have an installation image with a clean Awesome based install you can always update from there so that it shouldn't be much of a problem that there probably won't be an Awesome spin with every release (feel free though to convince me that Awesome is exactly what I've been looking for in terms of efficient desktop usage; if you manage to do that, this might change things.
And as I mentioned before I'm pretty open to tiling solutions - and I'd much rather learn LUA/Awesome than Haskell/Xmonad!).