It's a bigger deal on bigger aircraft, but on mid-size narrow bodies it's not as much of a problem. A 737, depending on the model, only has a difference of about 20-30k lbs between MTOW and MLGW and no fuel dump capability. An overweight landing isn't really a big deal in one, just a quick maintenance inspection. Closing the gap so MTOW and MLGW are equal is doable. It's hard to overstate how huge of an expense fuel is to an airline, if they have to lose some passengers and cargo they would absolutely do it if it got rid of the fuel expense.

Of course all that is contingent on having batteries with enough energy density to get somewhere close to current MTOWs while having something of a useful range.