For Beaming Defiance
in particular and not excusing white continually getting the short end of the stick when it comes to EDH, there were probably limited concerns thanks to magecraft. Any cheap instant already has a chance to be a combat trick in this set so the ones at common need to be dialed back a little from what they would usually be.
On other new cards, Plumb the Forbidden
seems great. Basically a cheaper, instant Reprocess
in the right list and cantrips as a floor. I really like that it plays around countermagic somewhat, which would otherwise be a significant risk when you're sacrificing a bunch of creatures as an additional cost. The in-set synergies with magecraft could be worth something too, though I haven't gone deep on those options yet.