Yes, YJs do ride nice. I just had the 5-leafs out of 4-cyl YJ too, so no custom pack. I also had the Spidertrax bar and bent my axle housing like a pretzel at Moab 2005. After that, I ditched the YJs and went back to stock springs. I guesseted the new axle housing on top and in the back, but have never put the bar back on since the YJs. I just took the rig out to Moab this past spring, and I didn't have any real problems with axle wrap.
Yes, you easily have enough lift for 33" tires. If I was going to run YJs, it would be to fit 33" tires, but I think you could run 33" tires with stock springs SPOA with a little bit of sheetmetal seam tweaking. I'm not totally against YJs though. I have a LWB project that I plan to run 6-packs in the rear, 5-packs in the front with 33" tires.
IMHO, I wouldn't even go SPOA unless I wanted to go with something above 31" tires as they will fit with a 3" spring lift SPUA. I like to keep my Samurais as low as possible-just enough lift for the tire size. They perform much better on/off-road as they have a lower center of gravity. 32=33" tires-go SPOA.