Departure from the comics
The new series - FTWD - is in the perfect position to offer something new and exciting to the fan base. Robert Kirkman said "The opportunity to make a show that isn’t tethered by the events of the comic book, and is truly a blank page, has set my creativity racing." "Fear" will bring a storyline that will be new to all fans, and not just those who are unfamiliar with the comics. The companion series will be a prequel to the television series, taking place during the start of the zombie apocalypse, showing attempts to control it, and exploring its origins. It's also supposed to feature a character "who briefly appeared during a key season one episode" in order to tie the two series together. So, the prospect of something none of us has seen before, that none of us can predict, is pretty attractive.
In contrast, I know some fans are worried that deviating from the comics will turn the companion series into something more like other shows on TV, and less like the unique experience TWD has given us. The thought being that TWD's success as a series is due to the proven writing and storyline that was already in place in the franchise, so trying to do something new and different may be a recipe for disaster. Some are even worried that if "Fear" fails, it will bring TWD down with it.
More than one way to skin a zombie?
We've enjoyed 5 seasons of TWD, and personally, I feel like I could watch 5 more at this point. However, somewhere along the line you have to wonder - what haven't they done yet? This is where opinions really start to differ, and you find out who the half-full & half-empties are in the discussion. Does this provide a creative opportunity for the writers to bring something fresh to the table that we haven't thought of, or will it bring about a stalemate situation where there are only so many ways you can approach the same subject matter?
Is too much of a good thing... a thing?
On the one hand, more of something you love is always better, right? This will give us our TWD fix almost year-round, so that nasty off-season lull we all "fear" (*groan*) will be a thing of the past - at least for the most part.
On the other hand though, part of what makes the current series so great is the fact that there really is nothing else like it on TV right now. It is this unique quality that keeps us coming back for more, and while it stinks to have to wait so long between seasons, that longing fuels an excitement for season premieres and mid-season returns. It may seem hard to believe, but more TWD could actually over-saturate fans in such a way that casual viewers may move on, causing a ratings drop. Shows get cancelled when ratings drop...