If Oden really wanted to save Wano and its people he wouldn't have believed Orochi's lie, and instead team up with Hyogoro and everyone else to fight back against Kaido and Orochi. Sure there may have been some deaths here and there because of the fighting but if they won and defeated both Kaido and Orochi so many more lives would have been saved and Wano wouldn't have become what it is now, also no one thinks Orochi is a good character we know that Orochi is a evil horrible person however some of us do think he is a good villain which is why some of us like him.
if he was really try to take down kaido and orochi by force. he will choose wb or roger crew to raid the country. thry are more formidable and experience than hyogoro or any samurai force. heck even roger, rayleigh and other already offer to help him open the border. but he choose to do by his own way.