While it is simply a strainer, it's an exceptionally fine one and they are well known to clog up and trash the rest of the transmission.
While a true pain in the rear, changing that $10 filter is far less expensive than replacing the entire thing. It's to a point where getting the transmission rebuilt will exceed the value of the car and for many, even a used box and the labor to install it starts pushing the envelope.
Honestly, if the auto trans needs to be removed for any reason (say a rear main oil seal), I'd highly suggest changing the trans filter.
While radical, one option would be to install a re-located drain plug in the bottom of the transmission, and using that hole, punch out the center of the strainer. Install an in-line filter in one of the transmission cooler lines.