Royal Galley has tricked you all by reminding you of Throne Room. Instead it reminds me of Caravan or Ghost Town. This turn, it draws a card and lets you play an action, effectively +1 card +1 action. Next turn, it's effectively +1 card +1 action again, but the extra card & action are spent on the same card you played the previous turn.
For the "next turn" assessment, isn't it more like playing a +2 cards +2 actions card (lost city)? Since you don't have to spend any cards/actions that turn to play the other card.
Yeah, that's what I meant. Royal Galley is like Caravan + Ghost Town. In the context of a deck that draws and plays everything each turn, a single Royal Galley nets you 1 card and 1 action every 2 turns. Additionally, it helps reliability by playing a card of your choice at the start of your turn. That's pretty good.
However, it's a different beast from Throne Room. When you draw your deck every turn, Throne Room is effectively a copy of another action in your deck, plus an extra action. For example, if I have a Witch and a Throne Room, I can curse twice per turn. If I have a Witch and Royal Galley, I draw one more card every 2 turns compared to Throne Room, but I can only curse once per turn. I think Throne Room is a lot stronger in terms of raw power, but is not as good for reliability.