After years of kicking around, I finally got to do something about it.
Some of you probably know about the Quick Highways preset by lzhl. It has been my go-to thing for armchair mapping of scarcely detailed areas — it greatly speeds up retagging village streets from track to residential, splitting solid footways into sidewalks/crossings, and adding surface. A few seconds of navigating through “heavy” presets saved on each road quickly turn into minutes. Which you can spend on taking a sip from your trusty Vault 13 canteen.
Which brings me to
Many buildings lack detailed tag values and are marked simply as building=yes. Good enough for mapping? Not OSM mapping! OSM data can be used in many ways by external consumers, including gathering statistics, and building types are a great source of statistics. This preset aims to do just that: remove points of friction for detailing the building value just as Quick-highways did it for the streets.
I’m still figuring out how to transfer my icons to the version published on the wiki with paths intact — if you have an idea, here’s the thread. In the meantime, the preset is available in JOSM Preset Preferences (if it does not display in the list, hit the "refresh” button). Feedback is welcome ;)

