Hello @neversatisfied
Great questions.
Speaking from the position as a retired AQ dealer:
Type 4 was a staple in the AQ lineup for years. I still use Type4 in one of my systems. I guess I didn’t want to say goodbye to an old friend, I suppose.
Type 4 is still consistent with AQ current design criteria, which is a good thing if you are/were happy with the sound characteristics of the cable. Rocket 33 gives you a couple of added benefits. A little more gauge overall, the the benefit of better materials. Type 4 uses what AQ refers to as LGC (Long-grain copper) throughout. Rocket 33 uses LGC on the larger conductors and the better PSC (Perfect surface copper) on the smaller conductors. This material uses an extrusion process that provides a smoother exterior surface for the copper. The typical result of Type 4 vs Rocket 33 is better impact, control and resolution, although a portion of the musical bandwidth will use similar material to Type 4. Rocket 44 takes a similar leap with more copper -- and better copper. The PSC used on the top end of Rocket 33 is used for the larger conductors on Rocket 44, and the smaller conductors utilize PSC+ (Perfect surface +). This process involves polishing the surface of the cables. With the Rocket 44 upgrade, we have heavier gauge AND better materials from top to bottom resulting in sonic improvement throughout.
Just an fyi that we are involved in speaker performance mods and use Rocket 44 in the vast majority of our projects.
Also, if you are okay with a little DYI, and if you can find AQ cables in bulk, you can save a lot of money if you are willing to order the terminations (and "pants") separately and do the terminations yourself.
As with ANY improvement under consideration, it’s best to audition those components at home in your system before buying. Rocket 44 has clear sonic advantages over Rocket 33 (and, Type 4), but I’d try them (or other considerations?) before buying.