The Deck of Many Things isn't really a trap. The number of negative and positive effects is balanced, with all black cards granting some sort of harmful effect and all red cards granting a beneficial effect. The point is that using the item is a gamble, and choosing to take a card is a major decision. If every card is grants a beneficial effect, then there is no risk involved and there is never a reason for any character to not take a card. A deck of spells is an interesting idea on its own, but I wouldn't replace the Deck of Many Things with it.
Rather than making it an infinite-use artifact with one charge per day, I'd cost each card as a single-use wondrous item and then cut the overall cost of the deck by maybe 25-30% for the randomization factor and make it function similarly to a Deck of Illusions. You can look through the deck to see what it contains, but it only functions when a card is drawn at random. The user draws a card and throws it out towards where he wants to target the spell; once discharged, the card becomes blank and can not be used again.