My thoughts on this are that it was inevitable. Nintendo always goes through many hardware revisions with their handheld devices. Just look at the Gameboy Advance. GBA->GBASP->GBAMicro->GBA-Backlit. I don't know if this is a deliberate tactic to double dip their sales, or if they just always want to put out the best product that meets the technology and price specifications.
In any case, the DS can only look better. I think the current design is pretty bad, it feels like a cheap plastic toy, and looks technologically ancient compared to the PSP. It's also pretty cumbersome to hold, and is far too big as a portable device. Just from these small screens the new redesign definitely looks sleeker and more stylish, as well as easier to carry around. Even though I don't do the handheld thing, the redesign plus the great games that have recently come out and are coming out do make it a far more attractive option.
And for anybody that's thinking of buying the DS, definitely wait until the new redesign is out.