I think this is a very important interface improvement for the Accordion.
I'm not sure I'm at the point where I think it is important. The Accordion stack has the ability to add an icon to each individual Accordion item. This means you can set the same icon for each of them (a plus sign, a chevron, etc), or have totally different icons for each. With hundreds of icons in the stack it shouldn't be too hard to find something.
Once the user clicks the Accordion item, it opens. At that point you have done your job. You've hidden the content to clean up the page, and gotten the user to open it either via your label or the icon, or both. Whether they choose to close the Accordion item or not that isn't as much a worry.
Just as you want to use Foundry-base stacks I want to keep some of the Bootstrap code as intact as possible, otherwise I'm writing my own version of Bootstrap from the ground up.
It isn't to say that this won't make it to Foundry at some point. It just isn't a high priority at this point since the stack does its job currently.
Addendum: I have added it to the internal issues and feature requests tracker.