Wow. That should be a high priority. It's simple and very high utility for the user.
FG's mapping overall is VERY underwhelming.
If a free javascript tool from the early 2000's (MapTool) can do lighting that automatically reveals hidden areas, can tile images, has clickable objects, supports hand-drawn maps, and multiple layers, I don't quite get why it's hard to do in something I'm paying for in 2015. It perhaps just hasn't been that important, but it is one of the things that, as a DM, I'm constantly running up against in FG.
I basically need to get correctly-scaled maps from
somewhere (that don't have a mis-aligned grid!), and use some kludgy fog-of-war to get the job done.
After a few months with FG, I'd say that this is the biggest thorn in the side for me. I like its combat engine, I like its drag-and-drop story elements. It was totally worth purchasing LMoP and running it. The fact that an errant mouse wheel spin can flip tokens or shrink/grow tokens is annoying, but not the worst thing. But the lack of a good built-in mapper is something I've butted up against HARD this week, and it's really.....annoying. It's kind of the achilles' heel of the program, and it's why I'm still not entirely willing to be an evangelist for it, and why, depending on what you're doing, I'd recommend you go with another tabletop.
If you wanna play the WotC adventures, FG is the only option, and it's pretty good.
If you wanna do your own thing...well, that's a more nuanced point.