Commanders horn should not be changed.
I feel like this card is perfect that way. If it's over powered then that would only be for gold cards that can pull it. Those should be changed instead of nerfing commanders horn which is basically just going to make people stop using it entirely. Right now it might only see play with NR and SC that have gold cards that can pull it. There's also a chance that players won't even play it like that anymore because it takes a gold and a silver to achieve value that other cards can do by themselves. No one is going to run this card by itself anymore.
I feel like this card is perfect that way. If it's over powered then that would only be for gold cards that can pull it. Those should be changed instead of nerfing commanders horn which is basically just going to make people stop using it entirely. Right now it might only see play with NR and SC that have gold cards that can pull it. There's also a chance that players won't even play it like that anymore because it takes a gold and a silver to achieve value that other cards can do by themselves. No one is going to run this card by itself anymore.