No reason not to hedge bets and make a move now. Even if the speculation that Photo can recreate your Aperture edits is true, you might not like the WAY it does it. Or other features. Or maybe you've got a new camera and Apple is behind on RAW (like mine). Or maybe you just don't wanna have all your photo edits in one basket.
I doubt anyone is gonna come up with an acceptable tool to import edits. We would have seen that already. But how often are you going back to those edits in Aperture? as opposed to re-editing? Even with some of my old photoshopped stuff and whatnot, and even though I have the tools to do so, some of the newer editing software is so good it's better to start over from the original anyway. And as noted, Aperture will be around for that. My copy is, even though I abandoned it quite a while ago. It's just an old tool you keep around.
So one strategy is that only new imports go into LR (although there are other choices). If you need a bunch of older stuff, you transition that. Otherwise you leave things be. In that situation, if I needed edits and/or embedded metadata, I'd export TIFFs into the finder folder where the masters were, writing metadata to xmp and/or jpgs as appropriate, and import into LR. Note that Aperture is still referenced those and can still find them. So you can either work forward from the TIFF, or redo the edits on the original.
What would be super useful IMHO would be a tool to export the metadata into jpgs and into XMPs for RAWs WITHOUT having to export. You wouldn't get edits, but location info, keywording, captioning, etc would be very very nice to have.
And that brings me to structure. The LR analogue to projects/albums/folders are collections and collection sets. How to replicate that for an existing group of folders, since it doesn't import? (Because LR just mirrors your filesystem folders, it's "import" (almost more like "show") function has no "import folders as projects" kind of deal.) For this I used keywords, since they can be hierarchical, and can be written into the files.
So you when you export a project/album like "2014 Wedding Project/Ceremony Album" you keyword all the photos with that (in LR 2014 wedding project>ceremony album). That way you can find that structure in that form even if it was stored in a finder folder called ~/Pictures/Family Photos. And in LR it's easy to turn a filtered selection into a collection, or use a smart collection. This way you can preserve some of the structure you're used to seeing in Aperture in the LR collection set/collection tab. And if later synchronize another edit or metadata (a very handy tool for use on folders within LR), it can bring up updated metadata and import new files. And if they have the same keywords, you could use a smart collection based on those keywords to replicate "2014 Wedding Project" or whatever.