Hyphenation and justification are a big part of why magazine production pipelines historically stayed in Quark/InDesign rather than TeX. Even with TeX’s excellent line-breaking algorithm, narrow justified columns will expose whitespace issues unless you tune hyphenation, tolerance, and sometimes switch to ragged-right for specific blocks.
In this example, the wide spacing you point out is mostly due to conservative hyphenation + full justification. It’s not something the layout engine enforces — the same frames can be rendered with different paragraph settings.
The “users - a” case is also a good catch. That’s indeed a source / micro-typography issue (ASCII dash with spaces instead of an em-dash), and TeX is doing exactly what it’s told. A real production workflow would normalize that early on.
One thing I’m exploring next is adding a baseline grid and better vertical rhythm control at the frame level, which should make it easier to mix justified and ragged blocks while keeping alignment consistent.
Your experience with Quark Tags is very much the kind of workflow gap this project is trying to narrow: not to replace DTP tools, but to make TeX-based pipelines more predictable and design-oriented.
I did some tests with Scribus but got to the conclusion that a huge part of the layout result is the hyphenation. There's that famous technical paper by Frank Liang about hyphenation in TeX called "Word Hy-phen-a-tion by Com-put-er".
Overall I think your layout looks great as a magazine layout. But for instance if you look at the third paragraph in the second page (starting with "The company hoped...") there's a bit too much white space between the words, I think. Also at the end of first paragraph (ending in "by end users - a first for the chip): it's pulling together "users" and "a" while it should be separated by an em-dash - but the problem could also be in the source - anyway there's not need to stuff that line with whitespace as it should be ragged left).