could we get "planeswalkers guide to ..." articles after a block's story when there is significant change to the plane? For tarkir it feels like it would be very different to see the before/after, or if they had been around at the time a story like alara's or new phyrexia.
Well, we did do one for New Phyrexia. And Avacyn Restored. Good news: what you're suggesting is basically what we always do nowadays.Whenever we generated new reference material for our own artists and writers for the creation of the set -- new world guides -- we turn portions of that world guide material into “Planeswalker’s Guide” web articles for y'all. If we have 'em, we'll show 'em.
Sometimes there's only one main world guide that covers the entire block (Theros, for example, but even then there was new material we showed on the web for Born of the Gods and Journey into Nyx). Other times, a set requires us to create a second world guide (such as Gatecrash or Avacyn Restored), and those sets definitely get additional Planeswalker's Guides.
Because we are crazy and hate free time, we built three entire world guides for the time-altered world of Tarkir. Two of those you've already seen as Planeswalker's Guides (KTK Part 1, KTK Part 2, FRF). There’s much more material to show you for Dragons of Tarkir, so there will definitely be more Planeswalker's Guide articles showing off all that work!