Mmmh, I think Itachi may not appear in the story for a while... he's the most important member of the Akatsuki, of course, but there are nine of them to talk about, and it seems the one we'll see the sooner is plant-guy.

And I agree that Naruto, given the kind of manga it is, needs to have some light-hearted chapters, but that can be done in various ways - for instance, when Jiraiya took Naruto to find Tsunade, there were various chapters completely dedicated to learning the Rasengan even before they even found Tsunade. Those were pretty light-hearted (specially if you don't count Itachi's appareance there) but not stupid. They relaxed the tension and the plot but didn't make it annoying.

So I'm kinda hoping the next arc will start like that too - some kind of traning or a mission that starts light-hearted enough and then transforms into something serious.
But I still say "ligh-hearted, not "ooh I'll cut these weeds faster than Sasuke!!" stupid.