The Standard Model has limitations in the sense it cannot tell us anything about dark matter, it cannot explain the masses of the neutrinos, the three fundamental interaction strengths almost unify at high energies (but they just miss each other instead), etc... There are many hints of "this could not be the end of the story".

Why did you give such a puny name (variously meaning 'thin' 'small' 'light' etc.) to something heavy?

Because it is funny? :D