Last night, The Flash dropped its big season 3 bombshell by revealing who archvillain Savitar really was. (WARNING - BIG SPOILERS FOLLOW).
Now that we know that "Savitar" is actually a future version of Barry Allen, the fanbase has had a big, vocal, reaction to the reveal. Taking that into account, and also where The Flash has been, and still needs to go, we're asking the question: Is the Savitar reveal a good or bad thing?
On the one hand, having Savitar revealed as a future Barry delivers a major emotional punch to all the characters on Team Flash - including Barry himself. The thought that Barry himself could murder Iris so violently (perhaps to catalyze his own transformation into Savitar?) drastically changes the major character dynamics - even if (when?) Savitar is defeated.
It is also set up for a larger conflict on the show, going forward: Barry having to deal with the fact that he's not as purely heroic as he once thought; that he himself is as much a potential danger to the world as any of the foes he's faced. The Flash always needs something dramatic to brood over - and season 4's drama could conceivably be Barry dealing with his fear of connecting with anyone, or trusting in his own power.
In the comics, this particular villain reveal was covered in "Out of Time," a story where Barry has to face an evil future version of himself. That storyline ended with Barry having no speed and being stranded in the ancient past; that would be a great place for The Flash season 4 to star - and possibly crossover with sister series, Legends of Tomorrow.
Finally, there's the warning that the Legends team found from a future version of Barry, during the "Invasion!" crossover event. That recording (in which Barry warns them not to trust him in the near future) suggests that Savitar could potentially replace Barry in the present timeline. That would be an interesting development, leaving other heroes of the Arrowverse to rescue the one true Flash, presumably from being trapped in the Speed Force.
Having Savitar be the future version of Barry Allen was something that fans called way early on in The Flash season 3 - to the point that comedic memes like "Barry Allen Really Is The Worst" have been launched to mock the reveal. Being predictable with big villain twists is a crime The Flash has already committed (see: the season 1 reveal that Harrison Wells was Reverse-Flash); this latest one arguably solidifies the fact that the show is in something of a narrative rut.
For three seasons now, The Flash has gone through the paces of ending a season-long villain mystery with the "reveal" that a close friend of Team Flash is said villain. It's also become a staple of the show to leave Barry in a state where he's brooding and lamenting the choices he's made since gaining his powers; seeing that same process again, now, isn't exactly high on fans' wish list.
Finally, The Flash has, in season 3, risked falling into the same trap as shows like Fringe - i.e., wearing out its multiverse welcome, with an overabundance of actors playing alternate versions of their characters. We've already had several versions of Caitlin Snow/Killer Frost; an angry Cisco, handless Cisco, evil Cisco; a whole montage of Harrison Wells; and now multiple Barry's (nerdy, Emo, evil) as well. There's only so much interest to be had in reinventing the same characters; Savitar Barry may ultimately be more of a letdown, than a person of interest.