I think it's more of a signal that they weren't replaced because they were incompetent, or something scandalous.
They were replaced because Zelenskyy wants progress, and it wasn't happening.
Now, whether or not this was a good move, or their replacements will be any better, or worse, is something that only time will tell.
Personally, I'm skeptical that the current circumstances allow for significantly better Ukrainian results. Moreso, I'm worried things could be going a lot worse.
Again, that's assuming nothing else changes in regards to the volume of military aid, or the capabilities being provided.