I'll add that to my "Why the Shapechange spell doesn't exist in any game* that I run" list ;-)
*Should I ever end up running official Missions, I'll have to grudgingly make an exception.
Meh. That is such a niche thing, and really only helps on downtime, giving you an alternative to paying for a hospital stay to help the healing go faster. Does nothing to help you in the middle of the run.
The limitations of Shapechange are harsh enough that, like shifters, while there are some benefits in niche areas, turning yourself into an unarmored nonmagical critter is just... not really worth it. Especially since you can't talk while you are shapechanged, and your gear doesn't change with you, which limits your usefulness on recon or B&E. And Combat is going to go poorly for you if you try to fight while in your critter form. Why do I know how bad Shapechange is in practice? Because I was at a table where one player was doing a 'joke' character, where the character was a mage who believed he was a monkey, and ran around as a monkey most of the time. And the limitations cost us a lot of money and rep as their antics kept the team from working together.
So it is a spell that, used well, can be useful (scoping the outside of a compound as a pigeon draws a lot less attention than a mage in the astral examining the wards). However, the limitations usually punish users who try to go crazy with it without the DM ever needing to get up to tricks.
That said, I have used a modified version of Shapechange, back in 4e, for Naga and other paracritters to take on a metahuman form.