Google is always making little tweaks to the UI during the developer previews, but there's usually a reason. The new Android O preview inexplicably swaps the cellular and WiFi indicators around in the status bar. It's very weird to see.
In Nougat, DP1, and earlier, the WiFi icon is to the left of the cell icon. That's nice because the angle of the WiFi icon and the slope of the signal line up closely—they nest together. With the WiFi icon to the right, it just looks awkward. I mean, just look at it above.
There's one other quirk that (I hope) is simply a bug. If you disable WiFi, the grayed out icon stays in the status bar, just taking up space. Gross.