The abstract game/AI designer Cameron Browne has put together volume 1 of a game design journal:
www.cameronius.com/gapd/issues/
A couple articles are available for free, both of which I enjoyed. . I particularly liked "Embed the Rules", a piece that explores the physicality of games and how to best utilize it.
It's not all abstracts; there's a piece on Risk and another one on Centipede as a board game(?)
I haven't subscribed yet but I'm thinking about it. It's not available digitally yet which is a shame as I think postage will kill it for me.