I haven't been flashed, but it's only cause I think the flash is a bad way of fixing the problem. If you're never going to raise boost or anything, get flashed.
Does your car hesitate? - THAT is the question. Apparently since you're not flashed yet, you don't have an issue with how it runs so I'd say no don't get the flash.
Every Mazdaspeed will "hesitate." We all have the same fuel maps. If you plan to modify the car, I would not get it flashed. If you're leaving it stock, go for it.