I felt the same way about that scene and thought about taking it out.

Without it tho, we really dont see that the Jedi are starting to have second thoughts about Palpatine. At least not untill after Obi mentions that they want Anakin to spy on him.

Without that warning dialogue from Obi, we go from Palpatine being worth launching a full scale rescue mission to save in the opening of the movie. Then for some reason now the Jedi want him spyed on. Without any prior reasoning.

This scene is letting us know that now Palpatine is gaining to much power for one man to have. And the Jedi dont like it.