If I were to identify the biggest problem this season, it was playing too well and raising false expectations, followed by numerous veteran additions which killed team chemistry.
Young rebuilding teams have a special chemistry, because expectations are low, young players can make mistakes and learn on the job without pressure and develop a core of starters who play together and bond. That should have been this season, with Franco at 3B, Crawford at SS, Kingery as Zobrist Jr, Altherr in RF, Williams in LF, Herrera in CF, Quinn coming up, etc. Instead when they brought in Santana and Arrieta, they started creating expectations that they would compete, and then all the veterans before the TDL reinforced that attitude.
Problem was the rebuild was still in progress, but instead of kids playing every day you had a team focused on winning, not player development. Now bad luck contributed, Crawford injured, Altherr went south, Herrera went to Jupiter, Kingery should have been in AAA, etc. But I think there's also a psychology of a rebuilding team that was violated.
I'm not blaming anyone, when you're in 1st place it's hard to say we really don't belong here so we're going to just play the kids and have fun and not worry if we hit a downward spiral. But I think in a sense it was counterproductive, had they started slower, the kids got to play, and then got hot, they'd be in much better shape going into the offseason.
This offseason, instead of trying to add WAR, they should continue to focus on rebuilding, Machado is a wet dream but Harper at the right price, given his age would be a good addition. Ramos, if they think he can be a mentor, would be a good caddy for Alfaro and eventually Grullon. But Santana has to go unless you are willing to pay $20M for a utility player, because Hoskins needs to play 1B and we need to open up spots in the OF for Haseley sometime in 2019 and Moniak sometime in 2020. I don't want any more 30+ free agents - that's for two years from now when the team is truly competitive and just needs some short-term veteran patches.