These are neither urgent nor necessarily very important, but they'd potentially be nice to have.
First, and the lesser of the two: Thinner Squigs - I suppose I could probably alter this to some extent by changing the hardness setting of my pen input, but I feel like a thin squigs option for raw squigs mode would be aesthetically appealing to me, especially if it were to carry over to the shadow that superimposes with the Skritter version of the character when you're done.
Second, and somewhat more geared towards practicality than simple aesthetics - No-Recognition mode for writing. I suppose this might conflict with Skritter's purpose of being more than just SRS, so I definitely understand if it's never implemented, but as many people have noted before, it can be easy to trick Skritter into giving you a hint at the radical of a character you're uncertain about, even to some extent with raw squigs mode turned on. A pure no-recognition, self-graded writing mode would be nice. What I mean by this, if it's not clear, is putting the pad in free-draw mode, and then showing the shadow squigs and moving onto grading mode upon the user hitting the "show" button, or something like that. This would take the concept of the pen-and-paper study style that some people have advocated and remove the irritation/wasted time of swapping between pen and mouse/stylus all the time, and it would keep users more honest than the "imagine the character and self-grade" method others have suggested. Kind've a happy medium between the two, only somewhat lacking the real-life handwriting practice of "pen-n-paper mode".
Again, if these aren't implemented (or even considered at length), I'm A-OK with that decision by the team, but in the interest of being pesky (likely) and potentially contributing to the positive development of Skritter (dubious at best, though I like to imagine that my feedback had a direct impact in the decision to create "raw squigs" mode...), I thought I'd spit 'em out for consideration.