I’d like to suggest that the developers re-think the traitstone drops in Explore. According to the gemsofwar.zendesk.com articles I’ve read, it looks like the Explore difficulty level will increase the odds of getting Arcanes. But, it says nothing about increasing the odds of getting Runics. No matter the level, Runics seem to fall between the cracks. For instance, I just finished my 3rd run all the way through Mythic Bosses. I got oodles of Minor and Major Traitstones. I got 6 Arcanes and a Celestial. But NO Runics. That’s just not right.
A possible change would be to give mostly Minors/Majors with the non-Boss Explore battles (with a small chance of higher traitstones) and bump the whole curve up with the Mid-Boss and then again with the Mythic Boss. So, definitely no more Minors with the Mid-Boss (and it should have a preference for Runics). Similarly, no more Majors with the Mythic Boss (and it should have a preference for Arcanes).