I would like to see the active state themeable and not global. Right now all buttons, radio buttons, checkboxes, etc all share the same color when active no matter what the theme is. This makes it difficult to use different color buttons. For example I want a navbar at the top of my page, but I want them themed black and when active I want them a dark grey. The other buttons on the page I want grey/white. Right now this is not possible.
Yes, this is something I'd like to get in for 1.2 or 1.3. I will be a nice addition.
I simply wrote some code that includes my own custom active state class definitions (which essentially override the defaults) based on which theme is selected. It's a hack, but it served it's purpose. It's great to know that the active state will also be themeable in future releases.
Maybe it is also a good idea to give buttons a general theme class (ui-btn-a, ui-btn-b, etc.) besides the ones with the current state (up/hover/down). This way it requires less code in case you want to overrule a global definition like the active state styling.
For accessibility it might be even more important to make the ui-focus state themeable. Good example is the JQM docs where focus on buttons in the header is almost not visible.
update: and we could style ::-moz-selection and ::-webkit-selection as well for each theme
update 2: found another one... ui-br should be themeable too
An issue we have to look into when we are working on this: #5231
Theme: Made active and focus state themeable. Fixes #3750