I'm excited about the planeswalker rule change because it means I can
run all the Lilianas without reservation
Is this rule change entirely for Cube?
I mean, in which other format is this change actually desirable? It doesn't or at least is hugely unlikely to affect Limited, since I am not sure if the same Planeswalker has had two different variants within sets which were drafted together, and even then, both need to end up in the same deck... I am sure it has happened, possibly in some crazy draft format, but it certainly doesn't seem like an issue that is worth changing rules over. Constructed then? I would be very surprised if 'Planeswalker saturation' wasn't on Wizard's danger-list given the last couple of years of standard, and this rule-change likely doesn't help at all in that regard. I hardly think the inability to have two variants of the same named Planeswalker at once was stifling deck-building. I am also not convinced that it increases 'grok-ability' by creating the common Legendary keyword, given Planeswalkers already break basically every other rule in the game.
That said, I mostly play cube, where this change is awesome, so yey! Plus, I think that Jace ultimate is adorable, and it is only possible with the new rules, so yey! I just think that it would be interesting to understand the thinking behind it.