Was Steve Smith still under contract when ne retired, or would he be a free agent? He's the only attainable player (possibly - at his age and if he wanted to return) who has the same ability to quickly elude a defender at the LOS. I also wonder if Andrew Hawkins may reconsider now that he could potentially have a bigger role...not saying he can replace Edelman, as few if any can really do what he does.
Unfortunately, I think Amendola hasn't had talent similar to Edelman's since his initial injury in 2013 here. He is a good route runner with sure hands but lost his quickness and explosiveness with thr ball. With JE gone, Amendola and Mitchell would get more playing time and both are at least adequate, so the dropoff wouldn't be enormous overall, but the scheme versatility is the bigger issue. I don't think Cooks has a similar game as Edelman, even if he may have some physical similarities.
Not to br a downer, but now I really wish they still had Bennett. That 2-TE offense base alone would be enough to defeat many defenses. Maybe Allen will surprise us.
All in all, though, I bet the Patriots stand pat if JE is done. I have personally noticed a slow decline in his game and thought he wouldn't be featured in 2017 as much as a lot of people here...I saw him morphing into an Amendola guy who was money on third down but not someone who build your gameplan around anymore. His yards per target have dipped a lot, and while he is stil awesome, he was definitely moving towards that later stage in his career, which comes up very fast. It does help thst there are literally discussions on this board every day about how overly stacked the Pats are with skill players, and they will shuffle personnel as well as any team.