the DS lite improved upon the original in many ways:
-much much smaller, sleek design
-way better screen
-longer battery life
the DSi improved on the ds lite in this manner:
-twice as much ram and a faster cpu clock speed
-even larger screen
-camera, with built in image editor to boot!
-free shit you can download onto the DSi
DSi XL is basically the DSi except four times larger, so it's like an alternate version that some people may prefer.
would you call these "small" improvements?
Obviously more details are yet to be announced about the 3DS, so I would refrain from judging the handheld until we get more information, otherwise u r dum