Nick, what is the subject matter of your newsletter? Serious subject, or one that can be a bit creative? Age of readers (a slab like Adelle or Chaparral as you are using adds to easier reading for older readers... or more of a transitional type for younger readers)... I just did an economic/political case study book set in Jeremy Tankard's Enigma typeface... came out quite serious, but certainly not boring...

As far as the layout itself... again, depending on the seriousness of the subject matter, you don't HAVE to have everything block aligned... pics don't necessarily have to align with columns... just be somewhat consistent in your choices...

And even the size of the font could, in theory be "hipster-ish" .... meaning use something in the neighborhood of 20 to 24pt font... serif or sans serif as the body text... for a newsletter, you are not bound to use serif for body text...

BTW, though, just at a glance, the leading (line spacing) seems slightly too open... either make the font fit the leading you have, or decrease the leading just a bit...
Let us know your progress...

Thank you for the excellent feedback; and the detailed advice.

Subject matter: Charitable projects in different countries: educational, fine art, scientific. There's also a sizable Activities section which includes all the get-togethers the local chapters have (social occasions such as picnics). Overall it's more serious than creative. (Obviously serious doesn't have to mean boring.)

Readers: Disproportionately older, but some of the major charitable projects are related to K-12 education, so there are some young people and middle-aged parents with a keen interest. Slab serif (Chaparral) is an attempt to maintain readability for those who are a little older (in print and online—half of our readers just read the periodical on-screen as a PDF) while feeling a little fresher than our previous typefaces (Minion, ITC Berkeley).

Leading: Fantastic observation! I think I might've tinkered with the Character Style for some reason at some point and reduced the original point size of the body text. I thought I might have to revisit it but thought I might be splitting hairs--your observation gives me a solid answer that I need to revisit.

Gutters: Gutters are at 18 points. Would you agree that they are too wide?

Alignment: This is where I'm really struggling to have layouts with more tension, effective white space, etc. I think I may need to redo my grid (which is currently a 12-column modular grid on 8.5x11" paper, which is far too many columns, I'm finding) to a 5-column grid and leave one column empty or partially empty at times. I've tinkered with it and so far the effect has been still very blocky and static.

Here are some attempts to break out of the static blockiness the design currently suffers from. Unfortunately they rely too heavily on high-quality images. We don't have a lot of those, so I'm trying to redesign in such a way as to rely less on images and more on typography.

My two cents:

1. Forget about harmonical porportions for page layout in periodicals, that is great for books but for the pragmatic needs of something like this you have to build a modular grid.
2. Layout certainly lacks tension; symmetrical 3 or 4 column layouts are boring. Try using a larger odd or prime number like 7, 11, 13, 17, 19 or 21. Of course you are not going to use columns that narrow but you can use two or three for a regular text column and have an assymetric and dynamic 4 or 5 column layout; maybe a wider first column from time to time.
3. The alleys between columns are huge, they can be as narrow as the leading if you want.
4. Leading is still a bit too open by the way.
5. Let headlines break the grid on the right side.
6. Maybe you could trim a tiny bit of the letter sized page to make it more interesting.
7. Stick call outs between columns, they don't have to fit quite in the center of the two columns either. They can cut the last column only by the left or the first by the right.
8. Make the bottom margin larger than the top and the external margins slightly larger than the innner one.

For periodicals this is a better book:
http://amzn.to/2CpQIWg

Good luck!

https://upload.wikimedia.org/wikipedia/commons/c/ce/1882_Harpers_Young_P...