Yes, The Walking Dead is probably AMC's biggest show since Mad Men and Breaking Bad are gone.  However, the Season 6 ending for The Walking Dead left many viewers very disappointed with the cliffhanger as no one knows who Negan has killed.  AMC timed it so that the spinoff, Fear the Walking Dead would have its Season 2 premiere, and it just aired last night.  It is possible that this franchise might be doing things that will cause viewers to give it a headshot kill with the off switch, resulting in the death of the franchise. 

Forbes called the first season of Fear the Walking Dead "kind of a huge disaster".  It ended with the main characters getting on a boat in order to survive at sea after Los Angeles gets burned.  From here, it is revealed that the zombies can walk on water (actually, under the water) which means that the characters are not immune from the undead on the high seas.  There are also pirates coming after the show's token group of survivors. 

The issue with this set-up is it is different, and yet the same.  Like the characters of The Walking Dead, these survivors on Fear the Walking Dead are in locations that are just as anonymous as the forests of Atlanta.  Not only that, the Fear the Walking Dead characters will have to deal with the same groups of scavenger groups that are trying to take from other survivors, but they are on ships.  Is a pirate version Negan going to be making an appearance?

Not only is this open-sea setting too much like The Walking Dead, but it is not known how long the characters will be on the open sea.  Fear the Walking Dead isn't based on any graphic novel source material like its original The Walking Dead series is, so the show is kind of doing its own thing. 

Is the plan to have these characters on this ship for the entire length of the series?  If so, then it becomes a "survival at sea" show, and that could get very boring, very fast.  However, in a situation of a zombie plague, setting sail is probably the best option, but then what?  The show will then be about catching fresh fish for food and obtaining safe drinking water.  Unless they come to an island, then the show becomes a zombie Gilligan's Island. 

Critics of Fear the Walking Dead say that the show missed a big opportunity as it did not show how the zombie apocalypse truly affected the world.  The Walking Dead opens with Rick Grimes having slept through the initial zombie outbreak due to a coma, similar to 28 Days Later.  Wouldn't it be interesting to actually see the president and armies attempt to respond to the zombie outbreak as society falls around them?  Also, there isn't really any hint as to the cause of the zombie outbreak either. 

Yes, Fear the Walking Dead could have gone in a very Independence Day direction as it could have cut to all kinds of scenes where the government attempts to solve the zombie crisis.  However, it seems the vision of The Walking Dead series isn't zombies, but it is how this affects the average person.  It is probably good that they don't try and explain the reason for the plague as certain zombie films have tried that, and it just doesn't work.  It's better that the mystery is left alive, and The Walking Dead has only teased the possibility of a cause with the character of Eugene. 

So, yes, the zombie genre is all about showing the journey of the people, but if all that Fear the Walking Dead can do is give us more people, then why even have it, other than to piggyback on the success of The Walking Dead?  Considering that The Walking Dead might have committed a big mistake with last season's cliffhanger, there might not be a lot of confidence in this series.

Granted, it is possible that the initial success of The Walking Dead could keep it on television indefinitely, as the graphic novel series is still going.  Eventually, the series could catch up to the graphic novel, which means the show either takes a hiatus or just plain ends. 

Every show, no matter how big, always ends up "jumping the shark".  That's a term from Happy Days describing the plot of an episode where Fonz actually does that, and most say the quality of the show just went down from there.  It is possible that The Walking Dead just "jumped the shark" with their cliffhanger and we'll see how the show can recover when it returns in October, and as for Fear the Walking Dead, they are out in the ocean, where there are several sharks to jump there.