It's nothing new, we've been doing this inspection for years as part of the ALI tasks.
It's a bit of pig to do, especially trying to remove the sealant in the centre post lower node area prior to the inspection.
The repair used to be a big one involving replacement of the window frame(s) with all the associated strip including stress jacking the aircraft and removing the skin panels around the windows.
I assume that the reinforcement repairs mentioned in the AD are a fairly new thing, I know Airbus were working on a repair scheme a year or two ago but I've never seen one done. It would certainly be preferable to replacing the window frames.