From what I could make out of the Japanese technical specs (which isn't much considering I don't know a lick of Japanese), we're still working with an Arm7.  That still means, in the event that we're able to even use a flash card, that we can still program homebrew via C/C++.  

Personally, people (especially you noobs), I would wait until the Japan release and see if any of those DSi's will run our current flash cards.  It's quite possible that we might be looking at getting brand new flash cards in order to bypass the region locking and to handle the newer roms.  Speaking of the DSi roms, I'm thinking they might become easier to dump, what with the SD slot, but that's just theory.