I think you have to have part of the old in order to pass the torch to the new. I think we'll more readily accept the new cast if we can see the link between them and the old.
One one hand, they want to bring in new viewers, but on the other, they don't want to alienate (no pun intended) the die-hards who have kept Trek alive.
I see a lot of similarities with this and with what Nintendo is doing with the Wii. They pretty much know that the hardcore fans will, for the most part, always be there (regardless of the complaints) but if you can come at it from a different direction, you can pull in new fans as well.
I personally don't want to see actual pushbuttons and panels with flashing doohickies that look like they are from 1960. I want the interior to look something more along the lines of how the ship looked in ENT, only updated enough to account for the chronological time difference. The ship from ENT was made to look like a cross between submarine and a starship.
On the original show they did what they could to make it look like the 1960's idea of the future. Fairly clean and uncluttered. Basic colors. I'm sure there is a way to keep the same look and feel of the ship from TOS episodes while bringing the visuals of the technology up to today's standards.
I think we've seen so many movies with great special effects that if you stayed too true to the original look, you'd end up with something that didn't look believable anymore.
