Sprites? Sprites? Sprites? Well, if you really think it is faster nowadays to have a copper-like processing unit right next to the RAMDAC that can decode instructions and change the place from which data is feched in real-time, then be my guest.
Personally, i don't think real sprites are the solution.
However, a 2d processor that can work with bitmaps stored within the GFX-card's own memory (i.e. blitter) would be cool.
As for incorporating something linked to the video beam, such as the copper, well, interesting, but people would need a nice API to be able to utilize that across a wide range of GFX-cards. It is hard to see that hapenning, but it would be very interesting, especially for one reason:
A copper, as in the amiga, does not have to be limited to sprites. It can also be used for alpha-blending multiple streams of images, overlaying graphics.. etc..
Now an API for that shouldnt be too hard, I guess.
And the hardware design should be easy enough too. The copper could have an exclusive mem for storing its copperlists (no reason hogging the RAMDAC bus) - perhaps it would work...
but having a copper subsystem just to support multiple sprites is over the top?