I totally agree with you on that! Its far from a finished product. I, at first, was very keen to flash my device to i570EDDJB2, but couldn't seem to do that for some reason. Now, when I've finally managed to do it, I immediately removed it from my device and reverted back to i5700XEIL5 (i5700DDIK2 - original). Following are "few things" those I found wrong atleast with i570EDDJB2:
-- Home screens lag horribly, while we swipe.
-- Free memory, at fresh install, remains 40-50MB even after task-killing (70-80MB with v1.5)
-- Very small-size handle for pull-up menu. Thumb doesn't land easily!
-- The UI that samsung designed from Camera App look ugly (sorry sam!) and custom looks are not native to Android at all. (I don't know if it's possible either.)
-- I experienced some color-banding particularly with android widgets. Don't know if it's specific to i5700 display only.
I totally missed out butter-smooth transitions of my good 'ol cupcake, could not miss it out for more, and dropped back to v1.5 finally
I believe it would be much better if samsung enable v2.1 to run on i5700 only functionality-wise, and leave-alone the UI part atleast. We don't want v2.1 struggling along custom-UIs all the time, which are good for nothing. i5700 is not a power-house. Its only +128MB of RAM and Plain Vanilla is what we expect.