However, refinements to the Export dialog (and all other dialogs) will make MP even better.
The only reason to resize the Export dialog is to change the size (usually, enlarge) the size of the preview images. The options and controls themselves do not need to resize.
In the current version, resizing the dialog causes the controls to migrate to rational positions in the dialog. This is excellent, but regardless of the logicality of the repositioning of the controls, enlarging the Export dialog wastes a large amount of screen real estate because of the blank areas in the dialog that also grow when the dialog resizes (see areas marked in red, below):

IMO, resizing the dialog should resize the previews only. No other region of the dialog should change. Unfortunately the current layout of the dialog prevents this.
I propose a reorganization of the Export dialog (and the other preview dialogs to come) into 4 horizontal regions or frames (marked A, B, C, and D in the image above).
Region A: Dialog Behaviors: height does not resize when dialog resizes
Region B: Previews: height and width resize when dialog resizes
Region C: Dialog Options: height does not resize when dialog resizes
Region D: Dialog Execution: height does not resize when dialog resizes
Organizing the dialog into individual horizontal regions in this way (plus setting the appropriate control anchors) will allow the dialog to resize with a minimum of wasted space and improved utility as shown on the example above.