The Flash broke protocol in Season 4 by not making the main villain a speedster, but just because The Thinker is here doesn't mean the speedster villains are gone for good. Showrunner Todd Helbing explains why the series isn't completely done with speedster villains below, as well as one particular speedster he'd like to see make a comeback:
I mean there's certainly speedsters in the canon of Flash that we want to explore and we want on the show. Like Reverse Flash to me, personally, is one of my favorite villains, one of my favorite speedsters, so I'd love that guy to pop up now and then, you know what I mean? But I think it was refreshing, and it's just been a lot of fun this year not having to constantly come up with new ideas of how a speedster could pose a threat to Barry. So, it's fun, and it's new, and it's a new challenge, but I think having speedsters in the mythology of the show is never going to change.
So for that very small crowd of fans of The Flash who were outraged when the big bad for Season 4 wasn't a speedster, it's not like it'll never happen again. In fact, with Eobard Thawne's time remnants still present within the Speed Force, there's a good chance team Flash and Barry could have another run in with the villain if Todd Helbing and the team wants it to happen that badly. That said, with the way things are currently set up following the premiere, we can't imagine a Thawne comeback is happening anytime soon.
As to why The Flash went with The Thinker this season as opposed to yet another speedster, Todd Helbing might be hinting something as he tells Comicbook of the great care the team took into differentiating all the speedster villains. Since their skillsets were all relatively the same (fast), the difference had to come down to the impact they had on Barry psychologically. Reverse Flash had the psychological advantage of killing Barry's mom, Zoom had speed and took Barry's speed at one point, and Savitar was always one step ahead as he was a time remnant of Barry. It's possible they considered a speedster for Season 4 at one point, and then realized they were running low on ideas to keep it fresh and something more than a foot race between two metas.
As mentioned, there are quite a few speedster villains from The Flash universe that Barry has yet to conquer in the show. Whether or not guys like Johnny Quick, Future Flash, Godspeed or others make the cut remains to be seen, although if other worlds start making their way into the mix again, one has to imagine a speedster will surface sooner or later.
The Flash is all new Tuesday, October 17th at 8 p.m. ET on The CW. For a look ahead at next week's episode and Danny Trejo's debut in the series, be sure to check out this trailer. Those looking to find more great television to check out in addition to the Arrow-verse would do well to visit our fall premiere guide.