I agree with the spamming of DS was not optimal outside 5MWD, but it was a strong option when you needed it.
And nerf to that was required, but the Bonus action inclusion in it was not, and OFC making Divine Smite a spell was a change that no one asked for and most certain was not needed.
All it was required was:
Once on YOUR turn after you hit with (melee) attack you can...
Yeah but Divine Smite is available at 1st level now, has some free uses.
Moreover making the other smites trigger on a hit is a buff and making them non-concentration is a huge buff and IMO in terms of class power this new Paladin is stronger.