The devs have stated that this is done to prevent the potential loss of gear being swapped out; the game is coded to force you out of your menu during the points in the loading process where this can potentially happen. How many items would you be willing to lose before swearing off mid-load gear swapping altogether? At that point it would essentially function as a self-imposed “no gear swapping [i]at all[/i] during loading” situation that new players would have to gradually learn by losing who knows how many items. The fact that the game allows you root around in your inventory for even short spurts while traveling is a compromise on the part of the developers. Other games just lock you out of your inventory entirely. (΄◉◞౪◟◉｀)