They did studies; most players dislike them - and especially most players who play 'seriously'. Because they prioritise luck over skill.

They also tend to be a bit fiddly and slow to actually do. Still, I agree there's potential for them.

I've designed four or five cards (one was a split card) using dice, with only two actually appearing in sets. Like Vitenka said, die rolls favor luck over skill. There's some design space, but I feel its predominantly red.

I would imagine whatever you want the die roll for to be limited to the number of sides on the die. I would guess d6 to be the most practical. D4 may be more balanced, but I don't know if as many players would have those. After imagining what you can do with a die roll, it being limited to a number, you have to think ways to make that feel fresh or unique with each appearance.

The best way to understand dice roll cards is to look at coin flip cards and what they get shifted out for.

Magic is a game with an inherent randomness due to the shuffled library. This randomness is quiet subtle and kept outside the player's mind by happening in an entirely hidden zone (the library being face-down and cards within mostly indistinguishable unless the game allows to manipulate that state).

This means that the forefront of the game is about game pieces that interact with each other in a deterministic manner. On the spectrum of randomized and deterministic outcomes at its base Magic has established itself around allowing a randomized initial game state which can be explored (through e. g. card draw) and otherwise resolved in a calculatable manner.

This is attractive in a competetive game since it rewards (trainable) skill over (unknowable) luck - allowing players to "learn to get better" and understand to discern favorable game actions from unfavorable.

As mentioned this is a spectrum and individual cards can use randomization to create interesting effects. But you only need few of those to make those that want them happy.

Knowing your psychographics and what amounts of cards are necessary to cater to sections of the target audience is important here. Those that like randomization can be served with a few of those cards, while those that favor deterministic gameplay require more different game pieces to get an appropriate variance in their game states.

With less cards required to actually be random it becomes advisable to be more selective about the ways you can achieve impactful randomized events. Any additional required material - no matter how commonly available you imagine it to be - is an additional burden to the players that need to come prepared.

There is some historical momentum from back when coin flips were originally introduced into the game, but strictly speaking they are just a variant on dice rolls (two-sided die) and got grandfathered in - but are gradually phased out in favor of cards that do not use additional game pieces to achieve randomization e. g. that use shuffling of the already present game pieces (cards).

I'll consider from here on dice and coins equally Un-serious for that reason.

Outside of the game materials dice rolls introduce other problems into card design. Often you have to decide between

> A: Dice rolls with a favorable/unfavorable spectrum of results (i. e. "Draw d6 cards." generally favors high results). These are a balance problem and can be disappointing when properly balanced or be "too fair".

> B: Dice rolls where you avoid a clear delineation between "good" and "bad" results, but often invest more words into it, i. e. you create more wordy cards. This results in complexity.

The balance between A and B is something you have to consider not only in dice rolls, but also in other areas of design, but they come quiet pronounced here. In a cost-reward consideration the cost to get a good dice roll card done can easily not be met with a rewarding outcome, because you either made the randomization to influential for tactical players (favoring more deterministic gameply), or not influential enough to actually please those players of the audience that favor randomization in the first place.

A very big aspect of dice rolls not yet mentioned is that they are noninteractive compared to other forms of possible randomization (once again the default favorable method is using the inherent randomization of the library like seen on e. g. Commune with Dinosaurs or clash).

There are games that use dice as a major component of their gameplay, but also often being ways to meddle with dice. (Unstable just brough us some squirrely examples of how Magic could handle dice meddling in an environment including more dice rolls). These cards seem like a pay-off for dice, but they are actually necessary crutches to add some control to this game mechanics which is in a vacuum outside of a players control.

And that's important: Using dice in a vacuum just means adding variance to an effect that could be deterministic instead. Without crafting the environment this just means the gameplay is not calculated with the same ease - predictions about the game state after a game action is taken become less reliable and your "Deal d6 damage to target creature." game action may very well turn out to just deal nonlethal damage and be a waste od resources.

With these mechanics players now have to take into account more possible game states and more complex decision trees - but without actually having deeper decision opportunities. The unknown varaible is no longer a consideration of an opponent's counterplay, but the unknowable luck of the roll.

As stated above you cannot learn to be better at getting a random outcome - at best you can learn to cheat at dice.

So some issues of dice are:

• long-term reward of playing the game gets cut
• game states become more complex without becoming deeper
• player's have less control over their actions and are hence less invested in them
• getting a design involving dice rolls to be rewarding without being detrimental t the tactical aspect of gameplay costs more (time/effort/money) in both the conceptual stage as well as the testing stage

And while these are not all absolutes of game design, they apply to Magic as

• a game concept with a certain established game play that nurtures a certain audience (feedback loop here)
• a game concept that lends itself to more easily randomize existing game pieces