Something that annoys me a lot with recent versions of HA is that it does not play well anymore with yaml file configs. Your are mostly forced to configure things through the interface, that is ok but might be annoying and painful to do when you have a few devices with a little bit more complicated setup.

For example, I wanted to replace a light bulb by another one that has a different Mac address to replace another one exactly. Before it was as simple as changing the Mac in the config file. No it is more complicated.

Also it was very easy to review and backup the config files. Now it is less obvious.