Seen33...ever hear the saying "Size isn't everything"?
...
Well, sometimes thats flat out wrong, BUT OTHER TIMES, well that statement has real merit.
Consider what exactly that amount of storage is used for....it is mainly for three things: 1) rendered movies, 2) redbook audio and/or voice acting and 3) increasingy higher resolution texture game art.
Looking at that, considering that this is a portable system, is it really that important to have FMV intros and outros? Hell, was it ever really that important? Recorded music and voice-acting, they can be a nice little extra but again not really that important. (High quality music in particular is attainable with the right programming and compositional talent and amount of effort). And finally, high-res textures and background art....meaningless on the DS's screen.
In short, dont sweat it. What we have here is an N64 like system with decidely larger-than-N64 game capacities right off the bat. If anything, be worried that the 4 MB of RAM may end up limiting developers, but don't sweat this size contest when it comes to media.