A game-release represents an opportunity for a developer to show a consumer a game. Even with that opportunity, many consumers will still never end up playing a given game. The developer also has X hours to spend working on designing (and otherwise creating) that game.
With all that in mind, the idea that the designer has split time evenly between a handful of different games -- even if they're very similar "variants" and not completely new games -- is foolish. It amounts to using a similar model as those shady "100 Games in 1" bundles that you'll sometimes find in mall kiosks.
In our world, a world saturated with games everywhere we look, one that's becoming more saturated every year, a strategy of quantity over quality is madness!
This, of course, isn't a call to avoid variants altogether. Subtle variants can be very low-cost, and have the benefit of sort of "hedging our bet" a tiny bit in terms of whether or not people will like our title. It's just worth keeping in mind that quality is the goal, not quantity.
Modern games also tend to have a slew of "gameplay options," and as per our discussion about "what makes a variant," technically, every one of those gameplay setting combinations is a new variant.
I think we've all played some games that had some options that, if checked, would make the game horrible. Some games allow you to turn off critical gameplay features, ruin balance or pacing, or turn on distracting or noisy features. Arguments rage on about Super Smash Bros. and whether to have items on or off, but putting the items on Very High and nothing but Invincibility Stars would probably result in a dull experience.
One of my favorite examples of this is the Gamecube title Super Mario Strikers, a Mario-themed soccer game. The game had a quite powerful "tackle" move, but there were no penalty cards as in real soccer. The move was so powerful because it had essentially a 100 percent chance to take another player down for a few seconds, removing the ball from their possession.
The counterbalance to this move, the thing that made it so that you wouldn't just spam it all the time, was that if you were struck by such a move, you were awarded a random "item" (think Mario Kart style).
Now, I'm not crazy about the idea of random items coming in and spamming up this already-ramped up, tight soccer game, so I look in the options, and hey -- there's an option to turn off items! Great! Except now, the game is completely broken, and you've got to house-rule out the tackle.
That's an extreme case, of course, but there are other cases that I'll get into more in the next section.
Multiplayer games -- and I'm thinking specifically first person shooters, here -- will often have player-run online servers for people to play on. One of the perceived upsides of this model is that server administrators can change many of the game rules. I'm not talking "mods," exactly (I'll get to that in the next section) but smaller rule changes such as changing respawn timers, reducing gravity, or changing the way that weapons work.
While it seems like a positive thing, what we're doing when we allow this is we're allowing lay people -- essentially, just some dude who was willing to pay 20 bucks a month for a server -- to change game rules, and thus, to design the game.
As an example, one of my favorite online FPSes is Team Fortress 2. Most of my history of playing the game was spent with me trying to find a server that not only had good ping, a decent amount of players, but also, I needed a server that was actually running the game Valve designed -- "vanilla" TF2.
Sadly, there was no way to filter this out for the longest time. More recently, they've added some filtering options, but as of the last time I checked, there were still some mods that would go undetected by your filter settings. One rule that's notoriously hard to avoid is that of reduced respawn time, where the amount of time you have to wait after being killed is reduced, often dramatically. Valve, at one point, even had to issue a statement on its blog educating people about why this was a bad idea -- namely, that it made matches more likely to stalemate:
They provide a reward for the team that's doing well, in that if they wipe out a significant amount of the enemy team they're rewarded with a short grace period in which they can achieve objectives. Without them, we found teams felt like they'd been penalized when they cleared the enemy off the last capture point, only to have them all return immediately.
Their blog post had little effect, in my opinion, but the real problem was that Valve was in the position to have to make an "appeal" to people to not ruin its game in the first place. Most players, and hence most server operators, simply do not understand the sometimes counterintuitive ramifications of a rule change, and so they shouldn't be trusted with this responsibility. If game design was something that any random person with zero experience could do well, then we wouldn't need game designers.