So lets talk about space whales.
I figure they really could've used one or two more episodes where they build up Ezra's connection to the whales. Other than that I think it was the most appropriate way to defeat Thrawn.
Trawn's whole shtick is that he does his homework - he knows his enemies' cultures and background, and can piece together how they will act from that - unless the Jedi are involved. Multiple times in the series, however, Thrawn shows contempt for the Force. The biggest example I can think of is when he calls the Bendu's lightning storm "Jedi Devilry". The form of "Jedi Devilry" Ezra has always been best at is communing with natural creatures. Daggum druid Jedi that he is. Therefore, I find it fitting that the grand finale was the same stunt he pulled in that abandoned base so many episodes ago.
I just wanted to share this notion with some other nerds somewhere. Hope y'all enjoyed my rambling.