I've gotta say no here.

I look at it in this comparison.

Seismatoad:

Hp-105

Atk-85

Def-75

SpA-85

SpD-75

Spe-74

Those are his base stats.

Now lets look at Swampert, ( a much better choice ) 's base stats.

Swampert:

Hp-100

Atk-110

Def-90

SpA-85

SpD-90

Spe-60

In the overall layout, Swampert has 5 less hp, and makes up for it with 15 more in both defenses, he has 25 more base attack, and equal base sp atk.

And his speed isn't the greatest.... only big downfall.

So if you want to have a good water/ground type, I think Swampert would be a much better choice, considering he can take more hits ( Even though his speed is lower Seismatoad's isn't exactly amazing either ) and deal a butt load more damage, for easy ohkos.