The card doesn't seem very powerful. Ignoring the second half, playing 3 of them is just like playing 3 cantrips - the first Leap Frog is +1 action, the second is +1 card +1 action, and the third is +2 cards +1 action. Looking at the second half, I actually have a good chance to help my opponent when playing this. Assuming my deck and my opponent's are of roughly equal consistency, it's not worth it for me to play an action that has us both get +1 card or discard 2. My opponent will come out ahead by buying something else and getting free cards from me. Note that cards that have an opponent draw (Council Room, Governor) give a significant card advantage to the person who actually plays it. Equal gains are just not worth pursuing.
The victory card discard seems pretty harsh, especially since it seems like you'll want to play multiple Leap Frogs per turn. The end game will get pretty painful. If a treasure is discarded, do you just discard the next card, or discard it and then do something based on what that next card is? If it's the latter, you'd wind up in an infinite loop in decks that only have treasure. If it's the former, the effect doesn't really seem all that impactful - slightly helpful for speeding up cycling, but it may not be worth the extra time to resolve.
Overall, it seems like it will help your opponent too much early, hurt them too much late, and also be a bit of a pain to resolve.