The Flash has yet to reveal The Thinker's big end game in Season 4, but one co-star has assured fans that Clifford DeVoe's plan is indeed coming together. Kim Engelbrecht, who plays DeVoe's wife Marlize, can't say exactly what her television husband is up to, but she did confirm that the bus Metas and their powers are quite vital.
I don't know what the ultimate goal is. What I do know is that the bus metas are really important to his grander scheme. He needs those certain skills to accomplish what it is he wants to accomplish, so he's slowly weeding them out. It's a bit of a mystery, like playing a game of Clue with DeVoe. The audience only has pieces of the puzzle that they have to put together.
The Flash audience has the pieces to the puzzle, at least some, but none of them appear to be currently useful. A power-hungry villain scooping up powers to have as many as possible isn't difficult to understand, but its hard to believe Clifford DeVoe specifically needs every power he's gained so far to successfully execute a concise plan. DeVoe currently has hacking abilities, size alteration, effigy animation, and jinxing in addition to his telepathy and excessive intelligence; does he really need much else?
To reiterate, what one plan could DeVoe possibly need all these powers for in the first place? And why would he assume that he needs all of them, when he likely couldn't have even known what powers the bus incident would even provide? I can't imagine he foresaw all the possible outcomes there.
As it stands, DeVoe's powers sound like the ideal abilities to have in order to pull off a one-man heist at a closely guarded facility. People without powers can easily break into S.T.A.R. Labs, for whatever reason, so maybe DeVoe has his eyes on a building with actual security, like ARGUS. That would be odd, considering The Flash has done nothing to show DeVoe has any interest in the facility, but as Kim Engelbrecht mentioned, fans are meant to piece things together, so maybe that's just something we haven't figured out yet.
Whatever Clifford DeVoe's plan is, it's starting to derail a bit. Marlize mentioned in the final moments of the midseason finale that Barry wasn't supposed to be cleared of his charges and released from Iron Heights. Now occupying the body of Becky Sharpe, a.k.a. Hazard, The Thinker put his wife's fears and doubts to rest with the salty powers of a previously seen Season 4 meta, and Kim Engelbrecht thought what DeVoe did to Marlize was a bit messed up. Ultimately, though, she thinks he probably did need to drug her. As she put it to TVLine:
The timing is impeccable, because she is using The Weeper's tears. The ultimate goal is positive in both of their minds, so her using the tears is a bit warped. But the tears are actually necessary, because I think Marlize would otherwise completely pull out of the whole grand scheme. If [Becky] wasnt using the tears, I don't think Marlize would stick around for too long. I'm interested to see how far he goes.
The Thinker may be losing focus a bit, but now that he has Becky Sharpe's luck on his side its hard to imagine Team Flash will have any less of difficulty taking him down. That is unless Marlize can come to her senses and offer the team a clue of how to stop him. Kim Engelbrecht appeared to indicate that she could perhaps go in a new direction if those psychoactive Meta tears ever run dry, so maybe Team Flash should put out a welcome mat.