Been reading it lately, and it helps reduce my scrolling time. I've hardly read any, so you can recommend really popular stuff, too.
I've read Vagabond, 20th Century Boys, Claymore (years ago), and some berserk. I just finished reading Teppu, which I thought was an interesting subversion of a lot of anime tropes. I also liked that it was a short run (only 8 volumes). I guess I like seinen, but I've also enjoyed josei like She Loves to Cook, and She Loves to Eat.
Anyway, no shonen please. Hard mode: please nothing about high school
I recently read Fullmetal Alchemist since a podcast I like was covering it, and it's definitely one of the best "battle shonen" manga (especially considering that it's like 27 or so volumes in a genre that has these endless books).
And the battle party is totally secondary to the story which has amazing political intrigue, government conspiracy and the nature of humanity.
Each character really brings something to the table and there are very few characters that I can't remember. Lot of really good leftist reads of the series as well.