@anon1 & anon2: They all still are - while someone had said they fixed the inaccurate preview problem, they haven’t. I checked.
They will look janked up in the preview, however, when you save and actually look at your blog it will look like it does in the original live preview (just make sure to reset defaults save THEN customize).
So yes, you can still use my themes but they will not look like the end product in the preview and only will look right after you save and look at your blog. Not through the customize preview.
If you don’t like that I would recommend emailing tumblr support and letting them know how you feel (: Because this isn’t just a problem for my themes. It will be for a lot of themes.