Meguiar's Wash Plus always had the following weaknesses: How much pressure I needed to use, how small the effective working area was, and the marring aftermath.
Suppose I use an "abrasive" or "cleansing" approach during the wash process. In that case, I've got a lot of water both on the paint and in the mitt acting as a lubricant which reduces the ability of the abrasives or cleaners to bite into the surface and work effectively. This forces me to put more pressure down and load up the wash mitt more often, I'm working in a 1x1' or 2x2' section before loading the mitt back up, and I'm left with marring that needs to be cleaned up with the polisher afterward. Better to skip the Wash Plus entirely, just wash the paint regularly and go with a polisher, my arms will thank me.
I think the intent for Wash Plus wasn't to be used as a decon soap wax/sealant stripper, but to be able to bite against stubborn bug guts, certain grimy areas, or tar spots when you needed to, just load up on the mitt and tackle them with a light pressure approach. To really dig into removing LSPs, that took some serious pressure, and depending on how fresh even 2+ attempts on the same small area.
If Kamikaze can figure out how to improve on the shortcomings that I noticed with trying to use Wash Plus as a dedicated stripper, then I'd be willing to try that out until I see the standard Kamikaze price tag.