Blog commenting and login isn't working for me right now in China (plus it's long :) ).
I used the new interface for just a few minutes because it is a little too slow for my computer right now (the old one is just barely able to run smoothly if i use epiphany instead of firefox, stupid old computer). Here are my observations so far:
I got a "still learning" on a character which I learned long ago. I assume it is because it was a tone practice that i have gotten wrong enough to "unlearn." I guess "still learning" is true in a sense, but maybe "forgotten, relearning" would be more informative, if it's not too much.
Probably had this before and I just never noticed/commented on it, but the "Write this character" over the flash on every character seems redundant to me. Anyone who uses Skritter for more than 5 minutes I assume knows to write the character if they see a new blank canvas. The tone one is slightly more helpful in that it helps differentiate between a shadow for drawing and a tone test, but even that still probably isn't necessary, at least from my perspective.
Just curious why the "bad stroke order" is in the character look-up information instead of "feedback" like before. I understand maybe that someone is looking up the stroke order from that button, and then wants to report (therefore convenient placement), but it seems big and out of place for all the times you don't want to click it. I would vote for feedback still. Tangentially related question, it seems you took this opporunity to update/change a bunch of stroke orders (from my small sample size), is this to intentionally fix them or could they be bugs that need to be fixed
Also a lot more whitespace seems visible... is this where the defnition/pinyin practice will go? Otherwise seems like things are squished around the edges of the prompt. Could the vocab progress bars, or some rework of them, go there if not practicing pinyin, etc. I miss having that visual feedback on my adding word progress, though I agree it is not a crucial thing by any means.
Along those lines, the characters above the pinyin still seem a little small (but I remember something about that in a forum thread a while ago). I also have been wondering about the pinyin for each character that appears below the main pinyin. I see that if there are two readings now it eliminates the wrong one after you draw it. Is there enough info to just eliminate it before? I sometimes find myself cheating by looking at that prompt to guess which "jie" is the one in "解释" for example. Also if you could eliminate the definitions that go with the other reading that would be awesome.
Last and possibly least, the progress bar above the flash looks more out-of-place and uglier than before. Don't know if that is a color thing, styles clashing with the rest of the update, or just my own imagination.
I know that's a lot and probably not all that helpful, I really do like the new interface, simpler and more stylish at the same time. Looking forward to killing more characters with an optimized version of it and the new practice modes soon! :)