Been listening to this episode on my way to work, and a few things come to mind (mostly about wild shape).
There was a book series in the 90s aimed towards kids called Animorphs, basically a bunch of kids learn about an invasion of mindcontrolling alien parasites and are given the ability to turn into any animal they touch. While not all of it translates to my DMing, one big bit is that the instincts of the animal is there and oftentimes overpowering the first few times a given animal form is taken.
Regarding spellcasting, if a player was Wild Shaped and wanted to cast a spell I'd let them...they'd immediately drop out of wild shape because the magic giving them the animal form is redirected to casting a spell but I'd allow it.
And may I say it is so nice to hear someone else point out the spy-tential of the druid! It was literally the first thing I thought of when I first read about wild shape and it feels like no one else thinks of it.
Side note, has anyone run or played in an all druid campaign?