The thing is, it will be very rare that this card isn't at least as good as "+3 cards, +1 action". The only time it's not really is if it finds no actions at all. And +3 cards, +1 action is a very strong card that I've seen talked about here, and some people have said that it's too strong at any cost.
Now perhaps that's wrong because being forced to play an action from one of the revealed cards is going to be a little worse than playing any action in your hand. But I'm not sure how much worse.
Also, you might want to exclude playing other Commanders here, like Golem does. It's not an issue for Herald because Herald only plays one card. But what happens if you reveal a Commander and a Village with your Commander play? You play your revealed commander, thus revealing 3 more cards. 2 of them are actions, so you set those aside along with your Village. You now have 3 set-aside cards, but set aside by 2 different effects. But Commander just says "the set aside actions", so this would technically include that Village. Or if you don't want it to, you have to have 2 separate "set-aside" zones. Currently nothing in Dominion can create 2 separate set-aside zones where you need to keep the 2 sets of cards separate.