R' Hirschensohn's critics are right - he did want to find lots of leniencies. However, the critics are wrong about motivation. It was not simply a search for leniency (and anyone who does all the kulos is a fool), but part of his program to make religion a part of life, rather than something in tension with daily life. There is a sequence of letters in the short-lived periodical HaMetzapeh, available at Hebrewbooks.org, in which he lays out his desire to find leniencies, and is roundly criticized by many correspondents. And he couldn't really find all the leniencies he might have liked - as R' Soloveitchik says, sometimes one must surrender to the halakhah.
R' Mintz did a Bar-Ilan search for Hirschensohn, and only found one reference, in a Mishpetei Uziel. Clearly, then, halacha has rejected R' Hirschensohn's approach. But he's a major figure in American Jewish history, as well as Zionist history, as an approach that was not taken, but had such promise.