Yes. Walton had to go. For a myriad of reasons, he had to go. Poor planning, poor development, in-game decisions, etc.
That said,
I don't know why people thought a light switch would just flip. It takes time to implement change. That is why this move should have been made over the summer. But it wasn't. You can get guys playing harder, and you can change up rotations, but if the system is fundamentally flawed, which we know to be true, it's not going to fix itself overnight. The coach in me says that I wouldn't expect anything dramatically different until after the break, or during an extended homestand.
Having Gentry slide in at this time creates an additional problem, as he probably also knows he's just a placeholder until the end of the year. Again, with an off-season to make wholesale changes, he could have done a more thorough change. I think he would have been more successful in this scenario. A new coach coming in from the outside would be more inclined to scrap pretty much everything that wasn't working, given the understanding that if you bring in a new guy, that means he's the man for beyond just the end of this season.
The best you can hope for here is some player development and minor tweaks, unfortunately.