I can't remember a single name of a single character from the movie. But I do recall thinking this character, along with most of the others, was boring. How did he get a show, exactly? What more could there possibly be to say about this character? We already know his fate, so nothing will have consequence... I just don't get it.
I liked it, but I think the main reason people are excited is because Cassian Andor was a rare glimpse into the actual gritty side of the Rebels. It's not all nice and happy princess, Jedi, and smugglers. We see a dude off a guy because he couldn't escape the Stormtroopers and might give away intel. Plus, who doesn't like spy stories? Especially space spy stories!