Simple 32bit processors
Actually, some 32 bit processors are much simpler to use than the 8 bit fossils. For example in Cortex-M:


No "special" registers, like the result of an addition can only go into register A, or segregated data/address registers or the like. You get a set of 32 bit registers which all have exactly equal abilities. Less rules to remember. Compilers love this.
No head-banging segmented addressing modes. Want to read a word from memory? Well, just read it.
No dumb limits like "Oh man you want to multiply two 32 bit numbers that's gonna take a whole bunch of instructions!" Nope, just MUL. (Note: some Cortex-M0 cores have the 1-cycle multiplier, the cheapo ones have the slow one, everything above Cortex-M3 is basically a powerhouse, think like a Pentium Pro from the good old days, without any of the crusty x86 retrocompatiblity).
DIV instruction (not available on Cortex-M0 though)
No special instructions for IO. Everything is memory-mapped. Very simple to use.
32 bit timers in large quantity.
NVIC interrupt controller is a work of art. 


The only thing complex about the small ARMs is that there are less tutorials available for beginners, but if you search them, you will find them. 

Also, the manufacturers usually provide huge libraries of useful code. If you want to use them, you'll have to learn how. You're not forced to use them, though.

Get a STM32 or LPC dev board. It takes a bit of effort adjusting to the new toolchain if you're used to 8 bit, but after half a day you'll be up to speed.