i have a suggestion, out of fairness sake. why don't we allow JR & ft, along with any other wanton altcoin/Bitcoin 2.0 dev, to insert their own highly specific op_code function into Bitcoin source code that benefits their own business model? as long as it's open source, it should be fine, right? and we shouldn't care if they are a for-profit, let alone nefarious, business; ppl can just ignore them.
There we go, thats the cypherpdoc we know
actually, i'm quite serious. let me rephrase the exact same concept. we can let those guys insert an op_code of their choice which will be open source. it will therefore be usable by anyone and not owned by them. ppl will be free to ignore it by choice, therefore it can cause no harm. just like your spvp. why would you want to "prevent" them from doing that?
I wouldnt work to prevent it I'd evaluate whether it was a good idea or not. Same as anyone else involved with bitcoin development, so it depends on the value & risks. Wanna get specific? op_snark or op_weil-pair support so someone can implement zerocash right in bitcoin? What do you think? In or too risky? (I have a detailed rationale as ecash crypto is my thing, but I'll let you go first:)
There is scarce development and QA bandwidth though, and risk from complexity.
One advantage of sidechains is its a sort of meta-opcode - when you have it you can do nearly anything else, eg you can do op_snark without #including however many kloc of code for a snark library into bitcoind.
As GMaxwell said when I expressed on #bitcoin-wizards right after he connected the dots between his previous snark based covenant idea/discussion and my one-way peg idea to explain two-way pegs, I said "but would that be practical to put into bitcoin given the whole point of pegs is to avoid needing to make changes" and his reply as "well maybe, because its the one change to rule them all". So I think meta-op_codes have any an extra argument going for them.
(I didnt originally consider two-way pegs because I assumed that you need to find a way that doesnt involve changes, as the rate of pace of change due to risk is the problem I was trying to fix, one-way pegs can do somethings including live-betas but with higher risk of brown-out). one-way pegs explained here: https://www.mail-archive.com/bitcoin-development%40lists.sourceforge.net/msg02944.html
Adam