Traditionally in the West, dragons have represented the worst in human nature and a discordant aspect of society. Smaug and his ilk are manifestations of greed and symbolize the way society breaks down when gold is not permitted to perform its necessary functions of linking the rich with the strong. When this occurs, bad things happen, esp. in Northern European cultures. Gold is supposed to strengthen a society by being shared. When it is hoarded, inevitably there is strife. Tolkien's dragons follow this model, not only by being evil, but representing both a specific kind of evil and actually inflicting the damage that kind of evil inflicts.
Rebellion and strife destroy towns, and dragons do that. Hoarding leads the strong and capable to seek their fortunes elsewhere, and dragons do that. Hoarding invites invasion and destruction, by both presenting a tempting target and driving away those who can defend a region, and dragons' hoarding does that, too.
If you want your dragons to be appreciated on multiple levels, invest some depth in them and give them some symbolic meaning. My two cents.