You have it right. A dedicated trail rig for rock crawling will always have a solid front axle because it's stronger (or can be equipped stronger) and offers better articulation. Some obnoxious Jeepers will tell you that anything without a solid front axle is garbage for off road and that comment usually comes from the guy with street queen chromed out Rubicon. The stock jeep setups don't offer much benefit over IFS because they're still built for the masses and sacrifice articulation for comfort & safety. Of course, they have lots of aftermarket options to make them incredible off road.
The super flexy IFS we're talking about links the torsion bars & creates better articulation on the trail. The travel of the IFS is still limited but the suspension will balance out the VX more and provide increased traction when you're driving on uneven terrain. I usually draw a picture to explain it but essentially you give some of the solid axle trail benefits to IFS while keeping the IFS for improved road handling & ride.