Don’t think +1 PA is going to fundamentally upset its being countered by Arb, Hand Cannoneers, or Cav Archers, (and IMO performing slightly better vs. these units + ranged UUs is acceptable anyway).
Also a recent thread about that:
Think it’s a fine idea, and fully solves the issue of Samurai not being able to engage with units it has a bonus against. Don’t have high confidence in the devs being so bold as to try it, but I think it would be very cool.