I had a look a the Wikipedia "Precommitment" article to see whether precommitment is actually as inappropriate as it seems to be being portrayed as.

According to the article, the main issue seems to involve cutting off your own options.

Is a sensible one-boxing agent "precommitting" to one-boxing by "cutting off its own options" - namely the option of two-boxing?

On one hand, they still have the option and a free choice when they come to decide. On the other hand, the choice has been made for them by their own nature - and so they don't really have the option of choosing any more.

My assessment is that the word is not obviously totally inappropriate.

Does "disposition" have the same negative connotations as "precommitting" has? I would say not: "disposition" seems like a fairly appropriate word to me.