Riot, can we please revert some of the GP nerfs?

Hi, as Gangplank is my favorite champ, I noticed one thing: I can't even one shot caster minions with the new barrels. It leaves them with a tiny amount of health. Can we please revert the ignore armor nerf on him? I think that 50% was good enough, 40% is too low. Can we get something back, please?

P.S can we also let his ulti upgrades be undo'ed (through the shop button) ? I accidentally upgraded death's daughter instead of fire at will, aaaaaand I'm sure you know the rest.

can someone also share a good build for him?

Thanks you for reading, fellow player/Rioter/both.