As far as I understand:
You should use WOL, as an automation trigger (which means a trigger statement for the automation you should create according to the docs, no idea how to explain that more clearly 
) as in the past, to get a âpower onâ functionality.
But if you missed that in the past and have no way to power it on, you will be presented with unavailable as a state, as you canât power it on.
This seems to be the behavior that HA suggests for devices that canât be turned on by HA based on the PR text.
edit: just to be more clear about that:
As long as you use an automation to power the TV on using WOL as suggested in the docs, there is no breaking change for you.