What is a "slim shaker cabinet"?

It's a shaker cabinet with very narrow stiles and rails (vertical and horizontal strips framing the cabinet door). It's been a trendy cabinet design for a while now, probably on the way out.

That is not a good look as inset. It is a weird mix of modern and traditional.

Not a great look - proportions are "off" , making it look cluttered, and the opposite of what you want with thin stiles/rails. Pick one. Inset with a traditional shaker, or go full overlay and thin.

Both pretty below.

One of my favorite door faces from Crown Point is Fine Line - I think it does look best on frameless (vs inset, which would likely be too busy) but it definitely isn't "on it's way out." It's a pretty great look IMO.

I think the thin rail inset is gorgeous