Second Life lacked mechanics on the simple end for less skilled players. In Minecraft, digging a block and placing it on top of another block is simple, and a player is encouraged to do so within minutes of starting the game. Second Life has a huge learning curve to overcome before you can take the first step from being an observer to a contributer.
That may be true, but learning an entire assembly language sounds like a much bigger barrier than Second Life's scripting language.
It's not like anyone's going to have to learn x86 assembly language and some really complicated architecture before being able to do anything useful (dear god why did my first computer have to be x86??).
I did a quick count of 8086/8088 instruction variations, IIRC each one has a different opcode, at http://en.wikipedia.org/wiki/X86_instruction_listings
6502 assembly (http://e-tradition.net/bytes/6502/6502_instruction_set.html
), which Notch had originally tweeted a bit about possibly using (much to the excitement of certain game industry vets) until he said it was too complicated, only has 56 instructions.
DCPU has, at the moment, a grand total of 16 basic opcodes + 1 extended opcode. There's space reserved for up to 63 additional extended opcodes. For an assembly language, it's quite simple, at least for now.
Given that there's already community support building around this on github, there's very likely going to be tutorials written so that even an absolute newcomer to programming could grasp it. And if there's to be actual money involved with being good at it, I'd also expect e-books, if not actual paper-bound books written on "Teach Yourself DCPU Programming in 21 Days!"