My ideal game would not be players standing in an empty room, that is an absurd and illogical classification.I suppose the notion of intentional hyperbole is completely lost on you.
Consider that map design is the key factor that distinguishes the only unpredictability required.That is not how it works. It doesn't make a difference whether it requires the player to push an extra button to achieve maximum speed or not. All that matters in terms of predictability is how far can a player possibly move in a given amount of time. Within this "radius" of motion, the player can be anywhere after the amount of time has passed. They might have run as far as they can, they might have not moved at all, or they might have taken a significant detour. All that matters is how large this radius is, and that is only dependent on the maximum speed achievable. And to that end, it makes no difference whether the maximum speed is achieved by means of sprint, or is the base movement speed. Of course, if you're also against a higher base movement speed, it's a different discussion we should have.
If all players move and shoot at the same pace, how they navigate the level is the uncertain aspect of gameplay.
That is a skill that can be learned. You can play and develop an understanding of the gameplay for each map.
This means you can understand and predict gameplay simply from the map. (If all players are on equal playing field)
You wouldn't want to click a button that makes your weapon stronger situationally, similarly, I don't want a button that makes my movement stronger situationally.
You said "The whole challenge of any game where players compete comes from the fact that players can behave unpredictably, and you need to predict their actions."Sorry, I should've explained more carefully how competitive games work because my choice of words may appear strange to someone familiar with the topic. You see, no good competitive game is entirely deterministic. There is no skill involved if players always know what everyone else will do beforehand. The skill in a game arises from the fact that a player can choose to make decisions other players are not expecting them to make; that is, to make choices other players have not predicted. After all, if the opponent knows your strategy, they can create a counter strategy and beat you with it. So, you want to keep your strategy as unclear as possible. In other words, you want to appear as unpredictable to the opponent as possible.
How can you predict the unpredictable?
By definition, you cannot do that, do you understand?
The player NEEDS to be predictable, and that is how you competitively dominate your opponent.
There needs to be an element of the game that allows the player to make choices in such a way that their opponents cannot predict those choices all the time. Else the game is deterministic and the winner is known before the game even starts, which is not interesting or challenging. To that end, it is necessary for players to be able to behave unpredictably.
But let's consider this word that confused you more carefully. The statement that a player "can behave unpredictably", is not the same as "every action of the player will be completely unpredictable". Rather, it means that the player can make choices, some of which the opponent will fail to predict.
The problem here is that there's no predictability in the absolute sense. That is, as far as the opponent is concerned, they can never be 100% certain that what they expect to happen will happen. There only exists some probability that the player will do something. And when it comes to probabilities, something being predictable and unpredictable are not as much polar opposites as they are just two sides of the same coin. Nothing is ever completely predictable, but neither is it completely unpredictable. The difference between how predictable and how unpredictable something is is the same as the difference between glass half full, and glass half empty.
It's not the board you predict in chess, it's the other player. Same goes for Halo.
Your condescending tone is infuriating, but I'll play along.
You're misrepresenting your own reasoning. You are saying that sprint makes you as unpredictable as possible.
Which is a weak argument when talking about competitive gameplay.
The players are able to make choices that are unpredictable regardless of having sprint or not.
You can't say that adding another movement speed is more competitive simply because it is far less predictable.
For that to be true, the definition of competitive would have to be about guessing. The more layers you add to having to predict someone, the less competitive it is, because eventually there will be too many options to consider in the critical time-slot you need in a live game. This means that you have to make a split second decision without reviewing all the possible options, because you simply cannot review all the possible options. Therefore, you're blindly guessing one of said options. Without sprint, the choices are narrowed down significantly, and you are more effective at prediction. (Sprint stacks with thruster/slide/GP/SC) adding even more variables.
Being realistic here, Halo is an open sandbox, and anything you do can be unpredictable, but once you give the player an abundance of options, you cannot accurately account for all the variables, and then competition turns into a train wreck of guessing games.
Back to chess,
I never said you predict the board, that makes no sense,
I said you use the board to predict movement, which is accurate. In the same way you predict a players movement off the map.
Any competitive chess game uses a timer, that forces the players to move in real-time.
They can do this, because they are able to see their options, and account for them.
If each piece had additional movement mechanics, the decision making would have to slow down.
Which is more competitive?:
Staring at a chess board for 5 minutes figuring out your move,
Or, instantly moving based on predictable movements of your opponent?
The correct answer is the latter.
Back to Halo,
Since gameplay unfolds in real-time, you have to be able to predict movement, especially in correlation to the map.
Just like a game of chess.
Once you add mechanics that stack together, (sprint/slide/thruster/pound/charge)
you lose all efficient predictability in regards to timing,
Making the player exponentially less predictable only hurts gameplay.