I find that "follow mouse" mode helps alleviate this pain a lot: when you can interact with a window (mouse or keyboard) without having to bring that window in the foreground, you end up moving windows around a lot less.
I like tiling in general but doing it well requires a big monitor.
I don't know, I run dwm on my 11" wide(ish) screen laptop, and it works for me, certainly better than a more traditional WM: generally, the less screen estate you have, the more it pays to make efficient use of it.
If I'm coding in Clojure, I have a vim window on the left, and a repl and a plain terminal (mostly for leiningen and git commands) stacked on the right. I could set this up in a traditional WM: but [a] it would take (a bit) more initial effort and [b] more importantly, with dwm I can temporarily bring in extra windows (e.g. a web browser) and then get rid of them again without having to restore my layout from scratch.
I agree with you about focus follow mouse (though it can be more trouble than it's worth if you have an overly sensitive trackpad).
I like tiling in general but doing it well requires a big monitor.