iPad external display support
Way back last summer I was excited by the announcement that iPadOS would soon support external displays. Somewhat awkwardly, iPadOS 16 initially launched without the expected feature and it took until the 16.2 update for it to materialise.
Now that it is finally available, I absolutely love using it.

To experiment with the new functionality, I have an M1 iPad set up with an external trackpad and keyboard. Version 16.2 was only released a few weeks ago, so I have yet to test anything in anger, but this seemingly small feature completely transforms the iPad and how I use it.
Interacting with this update feels akin to using a desktop computer - at times it's hard to tell if it's an iPad or a Mac.
Prior to this update, connecting to an external monitor resulted in a barely usable letterboxed 4:3 view of the home screen. It felt antiquated to look at and wasn't suitable for anything beyond very simple tasks. Now though, Apple have been able to present a fully grown-up interface, something suitable for comfortable all-day use.
External display support builds on top of the new Stage Manager multitasking experience. A single display (up to 6K resolution) is supported, and users can work with up to eight apps simultaneously.
Size that matters
As much fun as I'm having working in widescreen, there are a few things I'd like to see improved. Stage Manager is very opinionated about how it wants an app to be sized and positioned. This takes some getting used to and it feels like it would be a whole lot easier to leave the window where a user originally placed it. Perhaps this reduces confusion for new users, but it creates a jarring feeling when switching directly from macOS.
By far the biggest issue I've faced is with third party applications not supporting multitasking correctly. Any app that behaves well with previous multitasking features such as Split View, work very well on external displays, but apps that do not are a mess to use.
In the screenshot above I'm using Shapr3D CAD software and that works exactly as it should, the app can be resized into any aspect ratio, and it looks great when run in full screen. However, other professional apps are hopeless.
Affinity Photo 2, Octane X and DaVinci Resolve (all released recently) are based on a fixed layout window, which means they just sit in the middle of the screen looking lost. Fixed layout apps have always been a usability disaster on a tablet, but now they are so much worse. Enjoy this image of Resolve running at its maximum resolution on a 16:9 screen.

A brand-new pro-level app, and it just looks adrift out there. There is very little Apple can do to improve this situation, third-party developers must simply follow best practice and put the extra work in.
Flexible friends
One thing I am loving is Universal Control. The crazy-innovative technology that allows a single mouse to fluidly control both a Mac and an iPad works with this set up too.
Using a single Magic Mouse it is possible to traverse from a MacBook's external display, onto its built-in screen, then slide across an iPad's internal display before finally landing on the external monitor. One gigantic user interface symphony that must be seen to be believed. A great way to keep a desk free from an array of input devices.
There are surely improvements coming to Stage Manager in the future, but before iPad can completely replace my Mac, I desperately need third-party multitasking to improve.