You people do realize Oda is the author, right? If Oden is highly regarded in the manga for his strength, it's because the author wants you to know that he is strong. Not that the author is a fanboy for a character who is much weaker than they are portrayed to be.
Oda has done that with Shanks and Oden. Kishi did it with Itachi "5 year old but wise as a hokage" Uchiha for example