I am replacing the timing chains and guides on my 4.0l. The 4x4 version of the 4.0l has a balance shaft where the 2wd versions don't, I am wondering if it would be alright to leave the balance shaft out. Just don't want any unwanted vibrations.

 

Not sure why you would leave it out?

It shouldn't be worn out, never heard of that anyway.
And if you do remove it you will need to add plates of some sort to limit oil flow out of it's bearing journal passages, or your oil pressure will be low with no restriction out those passages.
Oil pressure is Back Pressure, the oil pump provides more oil flow than can be used, so back pressure builds up, thats oil pressure.
Think of it like a sprinkler hose, bunch of small holes in a hose, if you turn on the water all the small holes get about the same amount of water spraying out, now what would happen if you made 1 hole larger...............more water comes out the larger hole and ALL the other smaller holes have less water spraying out.

But no there would be no noticeable vibrations, the balancer was added because the front drive line on the 2001 and up Ranger 4x4 was always engaged to front wheels, Live Axle.

People that have swapped in 2WD 4.0l SOHC engines(no balancer) into 4x4s said no vibrations that they could tell.