In simple numbers,
Water and Fire are surprisingly equal.
Fire has 3 weaknesses, but 4 resistances, which is good.
Water has 2 weaknesses, but 3 resistances, which is just as balanced.

Grass on the other hand has 5 weaknesses, and 4 resistances.
Unofrtunately, nothing appropriate seems to be doable to improve it.

Fire is strong against 4 and bad against 4.
Water is strong against 3 and bad against 3.
Again both looking well.

Grass though is good against 3, but bad against 7

It really has the most weaknesses, and is resisted by the most types.

I think it would not hurt if one of those 7 was not resisting it, perhaps Flying (meaning Gyarados, Gliscor & co would be weak to Grass then, not just their single quad weaknesses)

But I strongly beleive it deserves being strong against another type.
Obviously the ones resisting it are out of question. As are ones that have it bad enough (like Psy, Ice) and some just make no sense to make a relation to it (Fighting, Dark, Ghost, Normal). Which leaves exactly one, defensively great (meaning it can take another weakness), pretty elemental type: Electric.

As for the reasoning, there is already an argument for it set in the type chart: Grass already resists Electric for some reason. So it wouldn't be that farfetch'd if it was also strong against it, as is the case with lots of "elemental" match-ups.

What notable examples would be affected?

Well since most Electric types are pure Electric... it would basically mean that they would have to fear more than just Ground (which is quite a luxury anyway when you really consider it). Electivire, Ampahros etc.. Oh and Lanturn & Wash Rotom would be the serious victims of such change.

Personally I think it could work nicely if tried.

What do you people think?

be a desired change?