Scientific Names as Common Names (or Ranting is Fun)

I've decided to resume updating my blog, and the first new addition is this subject which has been on my mind for a while. I'm sure we've all heard of the "Brontosaurus" (explained in an older post here), one of the most popular dinosaurs for a period of decades. Sadly, despite its (admittedly) awesome name, it is not proper for use in scientific circles. Does this, however, mean that it shouldn't be used outside of scientific circles?
Consider this: Despite the fact that we refer to Puma concolor outside of science more often as a mountain lion (or depending on where you live, cougar, catamount, etc.), mountain lion is still acceptable as a common name. Because of this, perhaps 'brontosaur' could be adopted as a common name for sauropods, the long-necked dinosaurs. Indeed, this could extend even farther, to generalizing the term 'dinosaur'. To my other paleo-stricken friends out there, I'm sure that an innocent ichthyosaur or mosasaur being slapped with the term 'dinosaur' is like nails on a chalkboard as, in the strictest manner, they do not belong to the Dinosauria. However! I believe it's possible that 'dinosaur' could be accepted as a common name (like how we call certain animals by names of other creatures today, despite their not being closely related). If this were the context of the word, then perhaps Ichthyosaurus, Mosasaurus, Plesiosaurus, and Pteranodon could all be considered 'dinosaurs'; if not for being part of Dinosauria, then at least for resembling them. Just some food for thought!