2000F1504x45.4

i've got a 2000 F150 with a 4R100 (guess i got lucky to get a good tranny) truck has 160,000 miles, looking for a way to firm up my shifts, they are soft and sluggish. fluid has about 50,000 on it, getting ready to drain (everything, cooler, lines, TC.) and refill it. its solid for its miles, but the shifts from 1-2-2-3 can be kinda soft, and sluggish, especially at light throttle take offs, up to about 1/4 throttle, WOT kinda depends on how hot the tranny is at the time. Fluid smells a little burnt, but is still a nice, bright red (not sure what it looks like in the pan) so should i look in to modding the valve body, or just change the fluid, a lot of people say new fluid is like getting a new tranny, even tho this one has had about 10,000 miles of aggressive driving.