In today's slavish, weak-kneed rabbinic Judaism, it's nearly impossible to spot any maverick rabbis who buck the trend, who instead of inventing or perpetuating unnecessary stringencies, dare strive for flexibility while maintaining authentic halakhic integrity; rabbis who understand that "Torah Lo BaShamayim Hi" - Halakhah was not created to make the life of an observant Jew more difficult than it already is. Or in the words of one such non-conformist standard bearer, Rabbi Abadi, founder of Kashrut.org, "conforming to Jewish laws without unnecessary discomfort and confusion"
I think these rabbis deserve special recognition for their refreshing boldness and originality of thought:
Rav David Bar-Hayim, Av Beth Din of Machon Shilo who attempted to make the culinary lives of Ashkenazim living in Israel a little bit easier by issuing a halakhic opinion that lifts the ban on eating kitniyot (legumes) on Pesach, a wide-spread nonsensical Ashkenazi chumrah that has no logical basis.
Rabbi Yitzchak Abadi, formerly a posek in Lakewood, and currently a Rosh Kollel in Jerusalem, as well as founder of http://www.kashrut.org/. He is of the opinion that Jews should continue in the ways of the Tanaiim in figuring out for themselves whether a food product is kosher or not. Hechsherim are mostly superfluous; it's sufficient to read the ingredients intelligently. He uses his authority to bravely declare that, for example, one may eat a tuna sandwich at any Subway chain, whether under kosher supervision or not, if one follows some simple guidelines. See here, here, and here. In fact, do yourself a favor and browse this website a bit. It's an eye opening experience for most frum Jews whose minds have been cluttered by too many kashruth organizations' acronyms.
Rav Yuval Cherlow, Rosh Yeshivat Hesder, Petach Tikva, who very recently paskened that a single women whose biological clock is ticking may halakhically bring a child into the world without benefit of chupah and kidushin. See here for his progressive reasoning (in Hebrew) and his suggestions on how one should go about it while complying with halakhic requirements.
I would hope that in the current climate of ever-increasing illogical chumrot there are more such intrepid rabbis out there. Readers, your suggestions for more nominations in this category are most welcome.