Many new attack reaction cards will be created, but they will always be at the mercy of a Snag dragging them back in line
At the time of writing all of them are relatively inexpensive
Even though the humble Negate may seem like a better exchange of mana-to-possible-counter, remember that opponents are often tapping out to cast their huge Fireball and not expecting to see a Spell Pierce countering their spell as well as a Counterspell would, anyway
Meanwhile, Nazahn, Revered Bladesmith is oddly similar to Kess, Dissident Magea more expensive legendary version of a popular Commander card (in this case, Stoneforge Mystic)
Obsidian Charmaw Obsidian Charmaw is one of the best rates to destroy a nonbasic land while also keeping a relevant 4/4 dragon in play
So you can cast any and all instants, sorceries and dragons, and they can't be countered