Maggie

Yes, picas and points, please, with the ability to type phrases like 1p5 and p0.145. Been using that terminology for 20 years. I think in picas and points.

Everything I've done from RageMaker to Quark XPress to InDesign has universally been in picas. Please, please provide support for this measuring system!
Also, if you haven't started implementing it yet, please consider making it "point-based picas" like Quark XPress, where typing 18 and hitting Enter automatically converts the number to 1p6. Versus InDesign where typing 18 gives you 18 picas. When you are doing production page setting, it is a lot easier to do something like '+5' at the end of your current measure to nudge it 5 pts, rather than having to type '+p5' or '+.4166', all of which require a lot more non-numpad numbers or mental math that break up the flow.
 
EDIT: Did I mention that all entry fields should be capable of parsing math? I believe they already are, but if not, definitely something that makes life a lot easier for production staff.

Have you ever addressed this? Being able to see invisibles is a must for typography! I'm new to Affinity Designer, and am trying it out. Not being able to see invisibles is a deal breaker.