Until Harman releases the products that contain ARCOS, it's all guesswork. Even those who've been to Northridge to preview it won't know all the ins and outs until it hits the market.
To give it some perspective, the two units in my "old" SDEC4000 cost more than an MC-12, and they needed an SDP-5 (MC-8) or SDP-40 (MC-12) to even be useful. That was nearly a third of the cost of some Synthesis® systems, and that was before paying a pro calibrator a couple of $k to bring the JBL DACS out to do the calibration.
ARCOS will cut the cost and simplify the process, but it will not suddenly flatten the product to a one-size-fits-all commodity. Harman will guard its margins and parcel out the feature set in order not to cannibalize high margin products and services with low-margin consumer goods. Still, it will be a step forward at all levels, and the consumer/enthusiast will have to decide where the ROI is on an individual basis.
At one point, I just made the commitment to spend what I had to to get the best I could. I didn't ask if I could get the TOL calibration by buying a $10K system. I knew that if I wanted the TOL calibration to a) be available and b) have meaning, I needed to get the system it was designed to work with.
The MP-20 looks to be a fantastic product, but if I get one (or its JBL Synthesis® counterpart) I still fully expect to use my SDEC4000 with it to do the really heavy lifting, including setting the crossovers, the xo slopes, the PEQ, the response curves, and the dynamic output to the amps. I'd be really, really surprised if an MC-20 was prepared to do all that.
For one thing, I doubt that it can handle providing the active crossovers and slopes for bi-, tri- or quad-amping passive speakers. Most speakers, even high end, will already have built-in crossovers that would be a bear to defeat.
What I can afford, when I can afford it...