Adj CA's are neither good nor bad. They are tools that allow you to 'tilt' the axle.

If you have a taller lift, and you adjust for a higher caster to cure the flightiness, then you introduce steeper driveshaft angles and the possibility of vibes. If you adjust for better driveshaft angles, then the caster is too low and you hate driving your jeep. So - you use the adjustable arms to balance caster angle and pinion angle. In the rear, you aren't worried about caster, so you use them to align the pinion for the best driveshaft angle, which will vary depending on which joints are used. (stock and aftermarket shafts generally use different joints).

Premature wear on the joints will happen with any lift regardless of your choice of arms. The driveshafts will be angled upwards more, meaning the joints are operating at steeper angles than before the lift, right? The taller the lift, the steeper the angles become. This pinches the boots on the stock joints, and will eventually rip them and let the grease spit out. Lose enough grease, the joint dries out. When it dries out enough, it starts making noise, and at some point, fails. Disconnecting and flexing offroad allows the axles to droop more, causing even steeper driveshaft angles and more wear on the joints.

 

Your floaty steering is caused because you have 3.25" of lift and factory control arms. Like kjeeper10 said you could fix this with adjustable control arms or drop brackets. At stock height the control arms are close to level. One of the things this does is returns the steering wheel to center when you let go of the wheel. When lifted the arms aren't so level and the wheels don't have as much stability keeping them pointing strait. So this creates a less stable or floaty steering feel. Read through this link under suspension, and then caster in particular. https://www.jk-forum.com/forums/modi...bie-has-18617/