Thanks for the additional details!
The ability to choose a different icon for active/default states is on our list. We originally had it prioritized, but it bumped down the list a bit as we received various user requests that have been popular in the community. We use community feedback and the level of interest in particular features as a key driver for what we prioritize. So things that get a lot more interest in the community tend to get bumped up our list.
Edit: Icons per state is available as noted here: Icons and Colors based on States + Window Shades
Regarding the ability to transform an icon, that’s an interesting approach that I hadn’t thought of. We do transforms, layers, and masking internally for some specific icons. I worry that it might be a bit of an esoteric feature that might bring additional confusion for normal users. I’ve added it to the list and I think it’s an interesting idea that could really add some flexibility to the existing icon set if we can figure out a way to execute it in a way that doesn’t overwhelm! 
Yes, up to 7-days of history data does exist in SmartThings. It’s one of those things that when you open the box, the request starts getting bigger and bigger, so we’d like to make sure it’s architected properly to scale going forward. Here’s a link to another thread with a similar request: