As long as you're swapping in a locker already, there's no reason not to upgrade the shafts at the same time as long as your budget can swing it.
You'll also want to to look at reinforcing the housing as well. With 35" tires the question is not whether your housing will bend, the question is when the housing will bend with an answer of "sooner rather than later". There's plenty of discussion on that around here if you search. I'm personally planning on using this kit:
Artec JK Front Axle ARMOR KIT
Throw on a heavy duty differential cover to give that D30 some more much needed rigidity and it will almost be acceptable.
Thing is, though, once you add up the costs of regearing, upgrading the shafts, trussing the housing, etc (especially if you have to pay someone to weld it up for you), you're better off just buying a drop in Dana 44. You'll spend close to the same money but get an axle that's quite a bit stronger. You order it with the gears/locker you want and then you swap over the knuckles off your D30 and reuse your unit bearings, ABS sensors and brakes. They come with all the brackets to bolt up to your suspension so you don't have to figure that part out. It's a naturally stronger housing so you don't have to truss it. And the ring/pinion is much bigger and stronger and will last a lot longer than a D30 ring/pinion.
I'm sticking with stock tires and gears (or, at most 4.10's) and stock axle shafts so a truss will be enough for me since I can weld it on myself and don't have to pay anyone to do it.