I'm okay with the minefield since the whales travel in pods and their numbers could arguably exceed what the ring's cannons can handle. And even though it didn't destroy the whales, it accomplished the next best thing by making them flee for their lives. Had Ahsoka listened to her droid and kept her ship in the whale, she'd be jettisoned to who-knows-where and taken out of the equation. I don't mind any of that.
But so much of what happened thereafter was absurd, IMO. Thrawn rationalized his decisions regarding Ahsoka by referencing her unpredictability, and then flushed her out because she would, predictably, go straight for Sabine. So he expedited Ahsoka's approach to her before his team on the ground had secured the kill. All that did was sabotage Shin. There was no advantage gained by rushing Ahsoka out of the debris field; in fact, quite the opposite.
Thrawn started with Ezra as a lone threat, fully aware from the past of what he was capable of if he would be given someone/something to fight for. He was then handed Sabine in handcuffs and with her weapons taken away from her. He then eventually had Ahsoka's location in the debris field pinpointed to the exact coordinates. Yet he allowed all three Jedi to unify rather than dealing with each one individually. His only obstacle/threat is these three adversaries and making sure they don't undo his escape (which in modern SW can now include something like Jedi Force-pulling space vessels to the ground).
In the bigger picture, Thrawn has a 10-year benefit of knowing the lay of the land, the benefit of magical witches who can remotely divine Jedi whereabouts, the benefit of multiple armed aerial vessels, and a huge numbers advantage overall. His battle plans get thwarted and then he takes solace in the fact that at least he bought time to load secret cargo - but even just cursory scrutiny reveals that he would've had that time anyway without incurring losses or unifying three Jedi to oppose him later.
The gap between the way Thrawn is depicted in the novels and his depiction in live action is widening exponentially with every new scene. Thrawn's cleverness as a character is limited by Filoni's cleverness as a writer, so at the very least he has to be willing to break some of his toys to build up Thrawn to something close to what he's supposed to represent going forward. I guess we'll see how willing next week.