I'm fighting the same thing, only it cropped up after adding 1" coil spacers. I've replaced the tie rod, unit hubs and steering stabilizer, still wobbles. As you said, everything looks tight, I think I'll take my trackbar off and inspect the mounting holes closely.
the box itself maybe wore out
or check the unit bearings ( lift the front and see if the tire has play)
if its not visible its usually one of these two
Are you sure it's "death wobble"... lots of people throw out the term death wobble and honeslty havent experienced it..
If you're getting feedback through the steering wheel and everything tight (trackbar, control arm bushings, TRE's, unit bearings, ball joints)... it might be as simple as your steering stabilizer isnt functioning anymore.... <-- like NC Jeepin said...
I'ts not going to feel loose.. you need to pull it off and see if it's working properly...
stock jeep death wobble is usually caused by but not limited to---track bar,too much caster,to much toe in!!if track bar is good reduce caster to 5* and set toe to 1/16" in and ill bet it goes away.sometimes a good steering stabilizer helps but its only a bandaid.