Microchip wants Atmel

You can get STM32 M0 for 32 cents....

yeah. depends somewhat on how RISC is defined.

And by common definitions, the AVR is RISC and the PIC is not. (The PIC32, being MIPS, is of course RISC.)

As you suggest, there are no fixed rules as to what is RISC and what is CISC (or anything else). There are just a set of characteristics that are common for systems classified as RISC, and others that are common for systems classified as CISC. Key points would be:

The AVR has lots of mostly orthogonal, general purpose registers. The PIC has a single register, its accumulator.

The AVR has a load-store architecture, the PIC operates directly on memory cells.

The AVR has mostly single-cycle instructions and pipelining, the PIC has all multi-cycle instructions and little or no pipelining.

The PIC has a small instruction set, and each instruction is quite simple, but that doesn't make it RISC.