Nobody plays enough for reliable arcane drops, they bottleneck everyone’s upgrades. You can see my stats in this thread, 200 battles without a single arcane.
The only reliable way currently to get enough traitstones to fully trait an epic or legendary, is to stock on glory until the arcanes you need are available in the weekly pack (or the ones for real money, if that’s your thing).
Someone posted in another thread the comparison between how many are needed and the drop rates, you can see that arcane drops are indeed way too low (while majors are too high):