An alliance seems way too soon. Also figured
faaraGaara would be the one turned into a tree
Well Gaara might be eaten soon so who knows what happens to the Tree People when they do.
They are rushing the story. If I am right about the contract; they only have 25 chapter left to go through the story. That means they have to defeat Punk, the Tree people and deal with Nail. Having Nail be an annoying thorn in the side of the story that just slows down the plot is something they can't afford right now. As they are almost half through part two and they haven't resolved anything yet.
Also I think they realize people didn't like Bolt was the only one that could fight any of the villains. As it was boring and made most of the cast unimportant. So they are giving power ups to the important members of the cast so they can be on Bolt's level. The daughter getting Kurama when he is suppose to be gone. Cups with the sage mode. Salad going to get something. And Nail is going to get an upgrade so he can fight again.