It's only a matter of time once they are released in the U.S. for someone to hack the hardware. Once the person who does this comes up with the update, it will likely be loadable into your flash card, and it will work fine.
I've had a 1st gen DS for the longest time and was considering waiting for the DSi, but if it doesn't have GBA compatibility and can't run flash cards whatsoever, I might rethink the matter, as I'm sure a lot of other people will. They might lose a hefty chunk of sales if that's the case. I have no intention of buying yet ANOTHER flash card and essentially pouring $250 into a lousy handheld, so here's hoping something can be done. Hopefully there will be a way to disable the region lock as well.
Nintendo is being a real dick towards us modders, aren't they?
And Sakarra, I don't think flash carts will be replaced any time soon, considering you can't do much with a lousy 256MB of hard drive space.