Which team without a World Series win has the most reason for optimism heading into 2018?

When the Astros won World Series Game 7 at Dodger Stadium, they didn't just capture their first championship in franchise history -- they gave hope to the other Major League teams that have yet to reach the promised land. 
Now that Houston has been crossed off the list, we're down to seven teams without a World Series title: the Brewers, Mariners, Nationals, Padres, Rangers, Rays and Rockies. But which of those clubs has the most reason to believe that 2018 will finally be their year? We've ranked them below, in ascending order of optimism heading into next season -- because if the Astros taught us anything, it's that no mountainis too high to climb.
7. Padres
Why they will: Sure, they finished fourth in the NL West at 71-91 last year. But we just saw Minnesota leap from 103 losses in 2015 all the way to the AL Wild Card Game in 2016 -- and with the young talent the Padres have waiting in the wings, they could be next.
San Diego boasts one of the very best farm systems in baseball, with pitchers like Cal Quantrill and Joey Lucchesi possibly ready to contribute as earlier as next season. Combine that with a solid bullpen led by Brad Hand and the return of the mesmerizing Carter Capps , and the Padres might be able to throw their way into contention. And speaking of the Twins, Manuel Margot has been doing his best Byron Buxton impression out in center field:

Why they won't: Well, they were still 71-91. San Diego's prospects mean there are plenty of brighter days ahead, but an offense that ranked 29th in OPS last year will likely struggle again.
6. Rangers
Why they will: In a word: homers. A whole lot of them. Between Adrián Beltré, Nomar Mazara and Dinger God Joey Gallo, only the Astros and Yankees hit more long balls than Texas. Oh, and now they've got Willie Calhoun -- the centerpiece of the Yu Darvish trade and the owner of one of the sweetest lefty swings around: 

Why they won't: In a word: pitching, specifically the bullpen. Texas finished last in the AL in save percentage at 58 percent -- bump that number up to league average and all of a sudden the Rangers finish the year at 82-80, just three games back of the final wild card spot. And while there were bright spots -- namely lefty Alex Claudio, who turned himself into one of baseball's most dangerous multi-inning weapons -- it's unclear who will get the ball in the ninth for the Rangers. 
Doug Fister should add rotation depth, but Texas could find itself in a lot of slugfests next year.
5. Rays
Why they will: Arguably no team in baseball is poised to graduate more talent to the Major Leagues in 2018 than the Rays. Like the sound of a rotation featuring Chris Archer, Jake Odorizzi and Blake Snell? Here comes Brent Honeywell, the screwball-throwing righty who showed out at the 2017 Futures Game. In need of a franchise shortstop? Say hello to Willy Adames, MLB Pipeline's No. 15 overall prospect, who hit .277/.360/.415 in Triple-A last year to go along with defense like this:

Considering that the Rays finished at 80-82 last year, a youth movement might be more than enough to boost them into the postseason.
Why they won't: For starters, they share a division with the Red Sox and Yankees -- two of the best teams in the AL last year who show no signs of slowing down. If the Rays miss out on October, though, it will likely be because of an offense that struggled at times last year and now has to replace Lucas Duda and Logan Morrison.
4. Mariners
Why they will: Seattle hung around in the race for the second AL wild card spot until September, and Nelson Cruz, Robinson Canó and Kyle Seager form one heck of an offensive core. Jean Segura had a solid first season at Safeco, Edwin Díaz throws lightning bolts out of the bullpen and Mike Zunino finally emerged as a potential catcher of the future. 
Why they won't: The starting pitching was ... less than ideal. Aríel Miranda, Yovani Gallardo and even Félix Hernández struggled, while James Paxton's breakout year was interrupted by a couple of DL stints. Luckily for the Mariners, we happen to know of a certain available pitcher who might be open to moving to Seattle. 
3. Brewers
Why they will: Ryan Braun is still Ryan Braun. Travis Shaw, Jesús Aguilar and Domingo Santana all had breakout years at the plate. Top prospect Brett Phillips was solid in his first Major League action, and Lewis Brinson is right behind him. In an uneven NL Central, Milwaukee's lineup has pop and athleticism to spare -- basically a slew of guys who can do things like this ...

... and this:

Why they won't: With Jimmy Nelson expected to miss at least a good portion of the 2018 season, there isn't much rotation depth behind Zach Davies -- and the same goes for the bullpen behind All-Star closer Corey Knebel.
2. Rockies
Why they will: Once again, the offense will be there. Behind Charlie Blackmon's monster campaign and Nolan Arenado doing Nolan Arenado things, Colorado posted the fifth-highest OPS in the league last year, and there's no reason to think that will change much in 2018.
What has changed, though, is the Rockies' rotation: Tyler Chatwood, Kyle Freeland, Germán Márquez, Antonio Senzatela and Jon "Ghost Hunter" Gray formed a promising young group that got Colorado all the way to the NL Wild Card Game. With another year of experience, they might be ready to go even further. 

Why they won't: As long as the Dodgers remain in the NL West, the Rockies will most likely be competing for a spot in the Wild Card Game -- always a dicey proposition. And after a blistering start to the season, Colorado faltered a bit down the stretch, largely due to a surprisingly slumping offense.
1. Nationals
Why they will: By now, you know the drill. Washington has won the NL East in three of the last four years, and went 97-65 in 2017. Bryce Harper is Bryce Harper, while Anthony Rendon, Daniel Murphy and the newly-revived Ryan Zimmerman round out one of the most potent offenses in baseball. And in case that wasn't enough, they've also got a three-time Cy Young Award winner.

Why they won't: About the only thing more reliable in recent years than Washington winning its division has been Washington suffering a heartbreaking loss in the NLDS. They should be great in 2018, but they were great in 2015 and 2016 too -- before they fell just short in Game 5. Even with the acquisitions of Sean Doolittle and Ryan Madson, will the bullpen hold up enough to finally get them over the hump? Will the offense finally come alive in October? We'll just have to wait a few months to find out.