in my opinion, if i take away all my personal feelings on it and look at it from what my pov would be if i was working on this show i somewhat sympathize with them.
i feel this wasnt a writer decision, or a kirkman decision, but an amc decision.
walking dead is the most popular show in america, and its one of the most popular shows in the world, that comes with a price.
in season 2 amc forced the writers to stay on the farm to lower costs (which caused alot of people to quit)
they didnt kill off the governor in the season 3 finale because of how popular he was as a character.
its pretty likely the first half of this season was so slow because of how much building alexandria cost.
and then this, one of the best scenes ever, the one that basically made negan the superstar villain he was in his first appearance, was milked for money. in my opinion the negan scene is comparable to jason todds death in terms of just how amazing/impactful at the time it was for the walking dead.
as long as american tv is funded by ads, the writers will never be in full control, the more popular your show is the less control you have.
for example, look at hannibal. it survived for 3 seasons purely because it was so cheap that despite its terrible ratings 3 seasons in a row it was able to survive as a passion project/critical trophy for the network and serves as possible one of the best adaptions of all time and pushed the boundries of what was allowed on cable television more than almost any show.
in my honest opinion, had walking dead not exploded the way it did in season 2/3 when it got really really huge, there wouldnt have been a cliffhanger ending. we wouldve gotten the negan headbashing.
its kind of bittersweet.
on one hand, its popularity means for people like me, who likes shows like the simpsons, doctor who, ect because they DONT end, it means walking dead will probably go on forever (or atleast as close to forever as you can get in this industry)
but on the other you get a watered down product from time to time because money talks