In Plasma 6, sunset options that are infrequently-used, hard to support, break a lot, etc

I'd like to propose a few things to remove in Plasma 6:

1. The "Air" theme that currently lives in Plasma framework. This hasn't gotten maintenance in years and should live on store.kde.org if we want to preserve it.
2. The ability to configure icon sizes systemwide from the icons KCM. People use this setting as a way around using the global scaling slider to make things bigger or smaller, and it's the wrong way to do it. It only scales icons, so the proportions of everything look wrong. Also, it doesn't affect non-KDE apps, and even some KDE apps, so it feels like it's totally broken from the typical user's point of view. It's one of those "broken promise" features that needs to be universal to work, and because this can't happen, it can't really work.
3. The ability to globally configure the icon/text visibility on buttons. Same deal. It doesn't work universally, and applies to even fewer KDE apps. It's a broken promise, and fixing it it impossible.
4. Per-activity power management settings. They add a full dimension of complexity in the power management code both in terms of UI and implementation, and have few to no use cases which aren't served better by something else.
5. Launch Feedback KCM and all existing launch feedback animations. Instead, just use the standard pointer+spinner cursor and time it out after 5 seconds, without making this configurable.
6. The ability to set the font DPI on Wayland. We tried this once before, but people complained that they were using it to work around the blurry fractional scaling. However that's fixed in Plasma 6, at least for Qt and SDL apps.

Discussed here and already done in Plasma 5:

1. "Offer shutdown options." I have no idea what this does and probably no users do either. - see plasma/plasma-desktop!1280 (merged).
2. "Default leave option" in ksmserver KCM - this option determines which button is selected by default when the logout screen is shown as a result of pressing the power button when using the Powerdevil KCM setting to show the logout screen when pressing the power button. I think it's far too nerdy and esoteric to be shown in the UI, and people commonly misinterpret what it means due to its visual prominence, compared to the extremely narrow scope of what it actually does.

Discussed here and decided to keep it:

1. "Windows go below" panel visibility mode. This option is slightly silly and probably used by nobody. What people actually want is an "intelligent hide" feature that makes the panel slip into auto-hide mode when a window touches it. So I'd like to propose removing this placement mode and replacing it with such a feature. - Decided to keep it; see this thread: #16 (comment 575532)

If you'd like to discuss one of these things, please either start a new thread for it, or add comments to an existing thread for it.

And feel free to add more.