When there are technical experts stating opposing things it is hard for people like me to know what is true, Mike and Gavin certainly do think that it does reduce the functionality of zero confirmation transactions.
Mike and Gavin have not commented on Opt-in RBF as far as I am aware; you are confusing his comments on full RBF. But on what basis do you believe their expertise is greater than a dozen other parties?
You keep saying that it is opt-in however it is only opt-in for the sender not the reciever, the merchant will need to tell the customer to uncheck RBF in whatever wallet they are using in order to accept zero confirmation transactions and in some retail enviroments this would significantly reduce the user experiance to the extent that it is not even practical, it is adding to much complexity to the user experiance requiring people to do this. Transactions can only be "pushed" by the sender therefore opt-in is only optional for the sender not the reciever, and you should not expect retailers to start rejecting transactions based on this as well since this would also make Bitcoin increasingly unreliable in such an environment.
Furthermore when blocks do fill up we now already have child pays for parent for unsticking transactions without the negative consequences that RBF seem to have, so I do question how usefull this really is.
Just broadcast a non-rbf enabled transaction to my 26 digit, alpha-numeric, case sensitive address grandma, no big deal! What, you didn't uncheck RBF? God damnit grandma I told you that you had to do that 1,000 times. Now you have to wait 1 to 120 minutes for a transaction to confirm!
For me it is not even a question of greater expertise since it has also become about ideology relating to economics and politics, these are questions that most technical experts are not specifically trained to answer. I think that some of these more fundamental questions like the blocksize for instance are more concerned with politics and economics then computer science, which is in part why I do not consider the Core developers fundamentally changing the economic policy of Bitcoin a good thing. You might have spend a lifetime studying computer science but there are other people that have spent a lifetime studying economics and politics that do disagree with you. The humanities are more concerned with the study of human culture, as oposed to more objective scientific facts which is what computer science is more involved with.
I do not consider you to be an expert on economics and politics, I most certainly do acknowlige you to be one of the best experts in the fields of computer science within Bitcoin. However sometimes it can be the case that engineers can awnser some questions very differently compared to schollars in different fields of thought. The engineers are not always correct, especially in fields that are not within their own area of expertise.
In my discussions with various members of Core, I have reached the conclusion that most of them simply disagree with the design of Bitcoin, which by design allows the consensus rules to be changed by a sufficient majority of miners and users, independent of what any group of technocrats wish.
It is important to remember not to attribute malice where ignorance is equally explanatory. All of the devs I engage with are very strong in cryptography and computer science, which may make them less accepting of the fact that at its core, Bitcoin relies in the economic self-interest of the masses to govern consensus, not a group of educated technocrats. As an educated technocrat myself I can understand the sentiment. It would be better if math and only math governed Bitcoin. But that's not how Bitcoin is actually governed.
At the end of the day, if social engineering and developer manipulation can kill Bitcoin, well then we're all betting on the wrong horse.
Opt-in RBF is explained in some detail in the
FAQ on Reddit, linked previously to you in this thread; you say that you are open to other views, but you seem to have made no effort to familiarize yourself with them.
To be fair I do not think we have had enouth time to fully discuss and understand this issue, I was only made aware of it being implemented relativly recently.
That is peculiar considering that he has spoken out against it on twitter, I was not aware that he had not told the Core team about his concerns, I find that a bit strange, maybe you have a better insight on why this is the case. I am going to ask Gavin myself why he did not speak out against RBF when it was being implemented into Core, since I do find that rather strange.
I just checked his twitter feed and can find no comment on it in the last several months. As far as insight, Gavin is not very active in Bitcoin development and hasn't been for a significant time, before the recent blocksize drama. That he didn't comment on the PR was unsurprising on that basis, but he certainly was aware of it-- since he asked when the merge was being discussed in the weekly meeting if we'd talked to any other wallet vendors about it (though this also indicated he hadn't recently read the PR).
I see, I suppose his position on this issue was already made clear months ago, I have already asked him again anyway.
https://twitter.com/gavinandresen/status/581840219068076032In regards to you saying that Gavin is not active in development I certainly do have a different perspective, considering what he has done for the blocksize issue over the last few months. Since this is a very important parrameter for me and how I perceive Bitcoin, I consider Gavin to have been very active in development, maybe more in the wider sense of the word, in the development of the Bitcoin protocol. This is not to belittle the work you have done for scaling Bitcoin which has also been very important, though at some point I do believe that we should scale the Bitcoin blockchain directly which can only be done significantly by increasing the blocksize.