Oyakodon is one of the blandest dishes in Japanese cuisine (typically made with no sauces or spices - or just a tiny dash of shichimi), so I'm not surprised foreign travelers found it disappointing. Growing up with the context of the dish helps - and so does a sensitive tongue!
This, and the way Japanese taste sushi and sashimi is very different to most foreigners. So when locals tell you a restaurant is good, it is importune to note this is in the context of the local traditions.
