I've been doing Flash for about 9 years now, so here's my perspective. There are a couple classes of people that actually use the authoring environment.
Developers - Mostly looking a code, but may pop open an asset or movieclip to adjust the design or animation.
Animators - Tweening lots of layers of movieclips and audio. Apparently Hype doesn't do audio yet, and I haven't looked at how complex they can layer animations, think tweens inside of tweens inside of tweens. They also draw assets in the flash ide, so they need a vector tool.
Promotional - Split in to 2 categories
Category 1 makes ads and promotional pamplets, Hype would work for them. Category 2 makes websites like the ones in Hypes gallery. Both categories need the ability to drop in audio and video from time to time though.
Edit - I think the biggest obstacle they may have is the lack of vector graphics, both at creation time as well as runtime manipulation.