Is this a good itinerary for three weeks or should we change things?

Tokyo 3 Nights
Kawaguchi-Ko or Hakone 1 Night
Takayama 2 Nights
Kyoto 4 Nights
Onomichi 2 Nights
Hiroshima 2 Nights
Osaka 4 Nights
Tokyo 3 Nights

Should we maybe kick Hiroshima out to have some more time on the other places or what do you think? First time Japan btw.