JarJar was probably the attempt to inject fun into the prequels, yeah. I'd like it to be done better than that, but the beauty of the original trilogy was having something for everyone and several plots going on at once. When a franchise begins to focus on the core plot alone, some of the life goes out of it.
I think suggesting Jar Jar was supposed to be funny is a misreading of the film series as a whole. He fits in the typical 'jester'-role from stories like Ivanhoe, an insanely irritating and seemingly completely worthless character, who by the mercy of the knight is saved to the frustration of the audience and everybody around him, but then by a twist of fate ends up being useful in the end.
Anyone know who asks "Who are you?" at the start of the most recent trailer? I was thinking it might be Carrie Fisher but don't actually know what she sounds like. Plus acting and all that.