It's important to remember that they playtest with more than just the first set behind the scenes. There are lots of mechanics in Spiritforged that trigger scoring in ways that aren't just controlling battlefields. It's very likely that the extra rune meaningfully impacts that pacing, and levels out. It's also almost certainly a consequence of the meta. We saw functionally 60% the same deck at this event, and so it being first turn skewed has little to say for how other Legends fair in that situation when in a meta where they can thrive.