Some way to make it ridiculously low friction for existing hardware owners to get into Linux. Like, less friction than downloading an ISO, mounting it, and installing it on your computer.
Or make computers come with it when people buy them. (This is still vanishingly rare.)
**
As a power user... I still have a few issues, some that might be common, and some that might be quite rare/unique to me. For example, post-concussion I really can't stand low refresh rates, and screen brightness is important to me. During my last 2-month Linux experiment, I had issues with controlling those things which was a mix of hardware, drivers, Linux kernel, GPU modes, etc. These sort of issues seem to be less and less common in Linux, and I'm optimistic, but I also am hesitant to sacrifice my own health to make a switch away from Windows. (Mental health aside.)
And some games still don't work right, at least not on launch. Which can make me sad as someone who plays games socially.
As a photographer, I bought and use DxO PhotoLab. I've compared alternatives, and I like it much better. It doesn't mean I couldn't use darktable but I definitely don't like it anywhere near as much. (And no, DxO does not support Linux.)