I have a lot to say about the Reflection Principle but I'm still in the process of hammering out my ideas regarding why it is terrible and no one should endorse it.
I'm not sure what Reflection Principle you're referring to here. Google suggests two different mathematical principles but I'm not seeing how either of those would be relevant on LW, so perhaps you mean something else?
The Reflection Principle, held by some epistemologists to be a constraint on rationality, holds that if you learn that you will believe some proposition P in the future, you should believe P now. There is complicated math about what you should do if you have degree of credence X in the proposition that you will have credence Y in proposition P in the future and how that should affect your current probability for P, but that's the basic idea. An alternate formulation is that you should treat your future self as a general expert.
I've often had half-finished LW post ideas and crossed them off for a number of reasons, mostly they were too rough or undeveloped and I didn't feel expert enough. Other people might worry their post would be judged harshly, or feel overwhelmed, or worried about topicality, or they just want some community input before adding it.
So: this is a special sort of open thread. Please post your unfinished ideas and sketches for LW posts here as comments, if you would like constructive critique, assistance and checking from people with more expertise, etc. Just pile them in without worrying too much. Ideas can be as short as a single sentence or as long as a finished post. Both subject and presentation are on topic in replies. Bad ideas should be mined for whatever good can be found in them. Good ideas should be poked with challenges to make them stronger. No being nasty!