I accept that there is nothing grammatically wrong with starting a sentence with a gerund phrase, however, I do tell my AP students to avoid the construction because it almost always leads to the use of a linking verb as is the case with the example. If we all agree that requiring action verbs is preferable, then the use of gerund phrase as subject of a sentence should not be taken. I often have students write, ” by using the…” I simply tell them to cross out the ‘by’ and use the participial phrase instead.