Thanks for the clarification. Yes, it is a challenge to compile/condense the information from a 25+ page thread or worse yet several 25+ page threads! I think summary threads like
@weighted chinup's is the best solution. (And summary rebuttal threads as well.)
I can see how the ability to edit could be beneficial. But I'm hesitant to see any posts edited in such circumstances because it unfairly alters the context for the ensuing discussion. Responses were based on the original post and not the edited post. Sometimes this has important ramifications. (This is the basis of the 15-minute edit restriction.)
For example, perhaps respondents would have replied differently to the edited post. It may be unfair (and possibly misleading) for subsequent readers of the thread to think those replies were in response the edited post.