In some ways they are less feature rich, but in other ways they are infinitely better. The fact you don't have to do any special tricks to display sprites down the screen in different locations is very powerful. That's the reason SWIV has so many bullets (all sprites) on the screen. On the C64, you have to do horrendous timing hacks to multiplex sprites vertically.
It would have been nice if the sprites had their own palette, were wider, stretchable etc but we're stuck with what Jay came up with! With imagination, you can do some cool tricks however, especially re-using sprites horizontally!
On each scanline of the display, the Amiga hardware has to read the sprite data for each of the 8 sprites as well as doing the same for audio. With faster memory accesses they could have done more, but perhaps that bottleneck was too difficult to overcome back in 1984?
The Menace article by Dave Jones started in Amiga Format issue 7
on page 63.