Magic's frames are very old-fashioned in that there are several borders. There's the black (or white, or silver) border around the edge and then another border around the picture and the text box. Compare with the cards in a typical FFG game, which use no outer frames, minor inner frames and leaves more space to the art. Note how different types of cards have different frames:
FFG's promos do away with even more of the frame. Here's an example from Netunner:
The printing process plays a part. Older games had large borders because printing was imprecise. There are more off-centered cards in say, Antiquities, than there are in Zendikar. According to Rosewater they could aim for a higher quality but not all of their current printers would be able to match it. This also explains why Keyforge cards have borders, they use a different printing than FFG's other games.
Compare these designs with VTES, which uses massive frames:
The outer border is the same as Magic and, in general, VTES cards look very much like old Magic cards do worse. The space between the drawing and the text box is wasted and putting cost on the left alongside required discipline and card type wastes far more space than putting them on top would. Too much space is dedicated to the expansion symbol (top right).
This is the same card as above, but with a fan-made border:
It doesn't make any great changes but it's significantly better.