Putting the Potion on the deck or even on the discard may be more interesting, maybe with a higher payoff. Or making it not a cantrip, so it is harder to spam (to avoid ripping the benefits too easily).
Now, if you have two, one is guaranteed to hit, so this is kind of +1 Card/+1 Action/+$1.5, which is fun, but possibly less interesting than something that requires more work.
This "version" (may need tweaking) could be interesting:
Slipslop - Treasure
When you play this, you may return a Potion from your hand to the Supply.
If you do, this is worth $4, otherwise, this is worth $0 and gain a Potion, putting into your hand.
Cost: $2P
BTW, the Potion gaining could be great for midgame Vineyards. Also, the cards comboes well with Apothecary.