How do you think the story would have changed if Smug would've killed Bard?
Do you thinks Smug woul've taken over everything?
YES if smaug would've killed bard the I think the story would've changesd a lot. On page 198 in my book it (chapter 12) the reason smaug went to the lake town in the 1st place was to prove that he was king " They shall see me and remember who is the real King under the Mountain." So Yes If Bard had Died Smaug woul've gone back and possibly bilbo and the dwarves might have died as well.
__________________
"A hug is worth a thousand words. A friend is worth more."
