I'm not sure what it is that would make people say that changing fluid in a Subaru CVT is hard. Drain out of the drain plug. Fill it from the fill plug. Perhaps it is the process of running it to temperature, to get the right fill level? Frankly, that's not really that hard either. The Mercedes 722.9 transmission has a very similar procedure to get the right fluid level, so perhaps I'm just accustomed to it.
If you don't have a scan tool that reads real time transmission temperature, I guess it may seem to be a hard thing.