FLUDD is useful, not incredibly useful, but it does serve a purpose for edgeguarding. Same with Water Gun. Not saying its the best move, but its not the worst. It is simply unique.
And actually, Mario is above average, statistically.
Final Smash: 7/10
Throwing ability: 5/10
Add it all up, = 42. Divide by number of stats, which is 7, =6. 6/10 overall. 5 being average, I would have to say that is above average.