Allow legacy behavior for "Rearrange Artboards"
While I'm sure some people welcome Illustrator's new features for rearranging the artboards, I have found it to be finicky and weird. There should be an option that defaults to the center of the work area, like it used to do automatically. This new behavior, of having to select where the artboards go just complicates a once simple process.

Starting with Beta 29.7.1 the Rearrange dialog got a separate dedicated feature, currently called 'Align Manually'.
With it disabled, artboards get positioned instantly in the center of the canvas, as it behaved previously.
When this is enabled, you will enter the positioning mode after pressing OK — to allow rearranging only some artboards, to address this request.
With more than 1 artboard selected (but not all), the mode gets enabled automatically (and becomes locked).
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Audri, I agree, but I’d like to know more.
What if this worked only when some artboards were selected (this is the reason why this step was added, to allow partial rearrangement), and skipped when none (or one) were selected? Would this work for you? -
Audri Lanham commented
The new update (29.6) now makes it that whenever you rearrange artboards, you have to click to place the arrangement. I used the previous version to center all my artboards in the window, and it feels like an unnecessary extra step to have my artboards randomly placed in the file. I think this should be a setting you can turn off in the preferences for those who wish not to use it.