Did Epicurus Create a Finished Product?

That's a good question but my answer to that would be along the lines that whether you consider it finished or evolving, the key ethical insight of Epicurus was that the faculty of feeling - pleasure and pain - is the end point of the analysis (or the starting point). Epicurus doesn't give a set of rules to follow and he would be the first to say that one size doesn't fit all, and that circumstances change. But I think he would also say that the ultimate guide remains the faculty of feeling, so that's what we look to, even while acknowledging that it isn't a rule that is set in stone and unchanging.

I see this as closely related to skepticism and the limits of skepticism. Epicurus was looking for (and I think found) the proper perspective on the issue of certainty vs skepticism. We aren't ever going to find absolute truth, but we have good reason to be content with the "truth" that is available to us, and we don't have to / shouldn't agonize ourselves over standards of certainty that are unattainable.

this reminds me of On Moral Development, where Epicurus refers to the fully mature character as "finished product", and a character in the process of moral development as a "developing product"

http://societyofepicurus.com/synopsis-of-ep…al-development/

Also Epicurus did give instructions on innovation so presumably the founders considered EP as an evolving phenomenon, inevitably (and the assignation of authority to the CANON also seems to indicate this: the five senses, pleasure-pain faculty and anticipations are the ultimate arbiters of reality and of values, not Epicurus).

http://societyofepicurus.com/epicurus-instr…-on-innovation/

I would think certainly in the realm of scientific observation he would have understood that better data would mean choosing from options that at that time seemed possible. So no doubt he would have expected the scientific understanding to advance.

In ethics he really did not derive final "rules" anyway - that would have violated the underlying premise that there aren't any absolute rules.

In epistemology also he described how to use faculties without reaching conclusions on what the faculties would reveal, since circumstances change. This area seems to be the one where according to DL and maybe Cicero the later Epicureans did improvise, but I think as best I can tell the improvisations were harmful and maybe disastrous.

The two areas of divergence I remember as best documented are where Cicero says some Epicureans tried to defend pleasure be "abstruse reasoning" or some such, plus in DL where he says that the "Epicureans generally" accepted a fourth leg of the canon. Both of those seem to me to be attempts to compromise with dialectical logic, which is a road to ruin because you give up the original high ground that logic is dependant on the senses.