I find ticket lettering to be totally subjective and not just a measure of how "good" a ride is, as the original lettering was also based other factors like popularity, crowd control, etc. but I'll at least try and give modern day equivalents.
I would say the Fantasyland dark rides (and Pooh) are B tickets. Monsters Inc., Little Mermaid, Small World are C tickets. A D ticket would be like Star Tours, Nemo Subs, Millennium Falcon.
I think Coco will fall under what I listed as C tickets with better animatronics (which I don't think next gen animatronics necessarily make something an E ticket). Possibly could categorize it as a D ticket if there are drops or more exciting elements than just floating past scenes.
Wow Mermaid? That would be rough. IASW on scale would be good.