I have come to the following conclusion:
In the world of Torah, nobody has done what Artscroll has done to revolutionize Torah study. Countless millions of pages have been learned because of Artscroll [and its offshoots such as the "Mesivta Shas"]. People who would never open up a Gemara have finished Shas numerous times because of Artscroll. And that is just their Gemaros. Then there are all of their countless other sefarim.
In the world of Tefillah - Shlomo Carlebach. In his merit - millions upon millions of words of Tefillah have been said with kavvana and joy. Carlebach minyanim are ubiqiutous. Dati Leumi, Modern Orthodox, Charedi, Litvish, Chasidish etc. etc. EVERYBODY is doing Carlebach. As a person - he was engaged in very problematic behavior. But that doesn't negate the merit he has for revolutionizing davening in Klal Yisrael.
