Atwood uses a 1400W element......use to use a 1500W but went to 1400W to lower the amp draw
Suburban uses a 1440W element
RV Water Heater electric elements are fed by a 15A CB
As you stated ....Wiring & CB changes would be necessary
So NO....
Doubt anyone has done that as it is not that much of an improvement (cost/benefit)
1400/1440W element have a recovery time of roughly 6.2 gal/hr (based on initial 70*F water temp) ---even shorter time for reheat cycle (from 100*/110*F water temp)
Want faster recovery time.turn electric & propane on at same time (16.2 gal/hr ---70*F water)
Want hot all the time.....leave electric ON