Another good episode!
I take your point on small dragons re: the firedrake, but there's also a good argument for smaller dragons made by Wayne Rossi
here. He talks about how 'dragon inflation' has meant that there are far fewer dragons in D&D than there should be and would be if they were commonly horse-sized (as in lots of historical depictions) rather than gigantic.
I also feel compelled to add this firenewt ("Sir Salmon Saliva the Second", a PC in the Whitehack campaign I run for my kids) to the thread.