Change the slider for pen width to a rolodex type wheel.
Setting the width of the pen tool to precise widths is difficult using the slider. I often switch between 0.6 to 0.9mm for example. Being able to choose the size like the 'jump to page' feature should be a feature. Thanks!!
The slider should be logarithmic to give it more control on the low end and more range on the high end; I may care about the difference between 0.6 and 0.9 but I certainly don't care about the difference between 4.6 and 4.9.
Amber J commented
Or a drop down list would work too. I switch between .1 and .2 a lot, it takes foreverrrrr with the slider