I am no huge fan of NIN's music either, but look at the facts. The band just celebrated the 20 year anniversary of Pretty Hate Machine, and they were filling arena shows. If that isn't relevant or influential, how about the fact they just used connections with fans to raise money for a patient's heart transplant? The fact they gave away The Slip for free as a thank you to fans? The purchase options for Ghosts was pretty ambitious, and the viral marketing for Year Zero was beyond the scope of any other copycat campaign that followed.
While it is commendable that NIN raised money for a patient's heart transplant surgery, I do not find that much else qualifies Trent Reznor as immensely influential right now. I think that it was very big-headed of him to assume that he holds such a monumental and vital place in this world. We've seen major label, big-time performers accomplish similar things. There is nothing revolutionary about viral marketing (athough NIN did take advantage of it in a creative manner), giving away an album for free, or offering different packages for fans to choose from.