Well, the NeoGeo Pocket Color has a little brighter screen and its battery life is twice that of the GBA :P Anyway, I think they got the reflectiveness a bit too wrong and it ended up too dark, then again it might have to do with consumption (but I doubt it, since in tehse screens, the darkest means it uses more batteries... all pixels are on when the screen is black, all pixels are off when the screen is white. it is reversed unlike most screens)
Anyway, there is a rumour Nintendo are making new backlit GBAs. It seems pretty obvious for one main reason: Gamecube.
If you plan to use your GBA as a device with your GC, and there are some games that REQUIRE a GBA AND GC (like the upcoming Kirby no Koro Koro), how can you look at the screen in a dark room? A lot of people like to play with the lights turned off. And even with lights on, the lighting might not be ideal, and you would need some kind of light. The GC-to-GBA link cable does NOT Allow you to have light accessories because it covers the whole top of the GBA, so it seems pretty likely that by the end of the year we might have backlitted GBAs.
I surely hope this is true
but current early adopters of a unit might moan.