More complicated doesn't equal better, less complicated doesn't equal worse, what works for the song is what matters.
Re the Phil Collins fill, if it had been a whirlwind around the toms which he's more than capable of doing I argue that it wouldn't have had the same effect. One of the most recognisable and effective parts ever written are the four notes that start Beethovens 5th Symphony, and I would not be surprised if you're humming it now as you read this.
As for the John Bonham fill, that was recorded in a time before pro tools, when studio time was at a premium and at a time before people had the inclination or equipment to play and replay music parts to pick them apart. If it worked well enough at the time then it stayed in. And who knows, perhaps he and the band picked up on it but decided just to keep it in?
And as philrudd said, keeping signature parts no matter how simple (or complicated) in live versions of songs is essential whatever instrument is being played. When either of my covers bands tackles a song THE most important thing for us to keep in are those signature bits. My main band has a woman singing songs that were made famous by male singers, none of us will be playing the same instruments through the same gear and getting the same sound as the original band, it may not even be played in the same key, but as long as those "touchstone" drum parts or sections of guitar solo are kept in then everyone's happy.
