I think big improvement to weather depiction in sim would be forecast based modelling instead of report based modelling.
If you take forecast based modelling you have all the data for 14 days for the whole world and much more detailed regarding the weather parameters than metar based modelling.
If this modelling is implemented the weather can be truly dynamic with fronts moving and skies clearing up gradually, storms developing ,etc..
The only downside to this is that weather representation is not 100% faithful to real time. But, then, who cares, when prognostic data is so good that a 3 days forecast is almost completely accurate let alone the forecast for the duration of the flight and the zone you can cover in average time flight.
Do you have any plans of implementing this...?