Evangelion was revolutionary because of its use of fanservice, but not in the way most people think.
Evangelion has its fair share of the stereotypical (and oftentimes controversial) fanservice but, as a whole,
Evangelion itself is fanservice. In brief, the anime was made by and for the biggest otaku out there.
Showrunner Hideaki Anno never hid his love of nerdy entertainment, and this passion drove him to fill
Evangelion with the kind of intricate arcane mythos, real robot details, world building, and more that would impress otaku. However, this somewhat backfired since
Evangelion's fans tended to prioritize this fanserivce and overlook its life-affirming themes.