I listened to an interesting topic about that on the Dutch MacOsx Podcast about that.
I didn't used iMove so I can't back it up for myself but it seems iMovie 06 has grown up into a program that was really complicated to use.
You have to hold in mind that the iLife suite is created for home users, to have fun and to give you the ability to create simple things (websites, movies, music etc) in a simple way.
Exactly cause of the timeline, iMovie felt pretty professional from the beginning and people have been using it in a bit of a professional way (kinda shooting under Apple's Pro Applications wings for that matter).
iMovie is to create simple movies from family holidays or whatever, not to create your own 2 hour movie.
I guess it's fun being able to create your own movie but that sure wasn't what Apple had in mind so they re-thought it all over and went back to the basics.
In itself, iMovie 08 seems to work really well but it's just that people have been used to use that timeline and so... complains are flying in now.
Pitty, but in a way it's Apple's own fault of course.
