Let me start with a brief player survey: Who among you likes having cards in your hand? Like, a lot of cards in your hand? All of you? Great! And who likes not having any cards in your hand? None of you? Also great! After all, the whole reason people play Magic is to play cards, which naturally means that having more cards in your hand is better.
So, if I said there were two different mechanics, one of which required you to have as many cards in hand as possible and one of which required you to have absolutely no cards in hand, you would expect players to prefer the mechanic that rewards having cards in hand. After all, it's rewarding what players naturally want to do, so players should love it right? Well…
An Introduction to the Mechanics
It should come as little surprise to anyone, but those mechanics already exist in Magic. The mechanic that cares about cards in hand is from Saviors of Kamigawa, and is unnamed but commonly referred to as Wisdom. The mechanic that cares about having no cards in hand is from Dissension, and called hellbent. As for which one players preferred, players greatly preferred Hellbent. But doesn't that run counter to what players like? Are players somehow wrong, or thinking backwards about this? Well, it's not actually the players that are backwards, but the design ideas.
Hellbent and Why It's Great
Hellbent is an ability word that changes how a card works while a player has no cards in hand. For example, Demon's Jester gets +2/+1 while you have no cards in hand, and Twinstrike upgrades from dealing damage to creatures to destroying creatures if a player has no cards in hand. Regardless of what it does, Hellbent is always positive.
Make no mistake, players aren't wrong bout this. Hellbent is great! The secret is how players achieve hellbent. Now, players could play cards that allow them to discard cards, but the easiest way for players to reach hellbent is to simply play all of their cards. And therein lies the biggest strength of Hellbent. It rewards players for playing as many cards as they can by making their cards even better. Playing cards is the entire reason people play Magic, so having a mechanic that rewards playing cards is wonderful.
There's even one additional benefit to cards with Hellbent They add options to the game when a player would otherwise not have any. Cards like Ragamuffyn and Keldon Megaliths allow players to continue making choices and affecting the game, even with no cards in hand.
Wisdom and Its Failings
Wisdom is a term for an ability that cared about having cards in hand. It was used in a few different ways. One is counting the cards in your hand directly as on Presence of the Wise. Another is gaining a bonus if you had seven or more cards in hand, as on Akki Underling It can also be used as a bonus if you have more cards in hand than each opponent, as on Okina Nightwatch.
Wisdom is the exact opposite of hellbent in terms of play. In order to get cards in hand, a player could play cards to draw more cards, but the easiest way for players to get wisdom is just to not play cards.
Just draw your card each turn, and don't play it, then repeat until you have enough cards in hand for what you want. The problem here should be evident. Wisdom is a mechanic that rewards players for not playing cards.
For a specific example of just how miserable wisdom could be, look at the card Secretkeeper.
Imagine your opponent is at 4 life, with three cards in hand and no way to block a flying creature. You take your turn, draw up to four cards in hand, play Secretkeeper and pass the turn. Your opponent takes her turn, and without a way to deal with Secretkeeper can't play anything or you'll have more cards in hand than her and win next turn. So she just passes the turn. You take your turn, and draw a card that won't win the game. So, you keep it in hand in the hope of getting enough cards in hand for Secretkeeper to win. And so each player passes back and forth, not doing anything for several turns until each player has seven cards in hand, and you draw a card going up to eight and finally giving the Secretkeeper flying to attack and win.
What Players Really Like
So, we can see that although players like having cards in hand, it’s only because having cards in hand is what allows a player to play cards, which is what they really like. Further, we can see how even though a mechanic can look fun, it can end up anti-fun because of how it plays, and even though a mechanic can look antifun, it can end up playing well.
One just has to go through the steps of imagining how the mechanic would play out, and what a player has to do in order to use that mechanic.
If there is only one absolute truth that you take away from this, let it be: "Always consider how your designs will make players play the game, and make sure it leads to players doing things they want to do."