Then of course, there was a resurgent modernism led by the jesuit followers of Theilhard de Chardin. If there was a heresiarch, He is IMHO the best candidate. The irony is that his name is never mentioned nowadays. he revolutionm he helped start has long since buried his specific contributions.
Then there are the biblical scholars who latched onto liberal scholarship and like Luther et al. claimed to present a "true" form of Christianity beased on their scholarship. If Ray Brown weren't such a footnote in the scheme of things, we might name him.
That's a very good point - in fact, you're so right about the last part that I hadn't even thought of him in connection with this! But his thought certainly holds many seeds of the modern (as yet unnamed) heresy that pervades the Church, particularly this growing focus on the Earth and Nature.
I remember reading him when I was a teenager. His works struck me as very poetic, more in the line of meditations than anything else, and not meant to set forth any doctrinal points. However, if examined from that point of view, they are stuffed with dubious doctrines, and his vague, mystical visions hold some dangerous things within them.
There used to a saying that mysticism is dangerous because it "begins in mist and ends in schism." I think one of the reasons Teilhard doesn't get more blame for this heresy is that it's quite possible that he didn't see himself as believing anything that was not in consonance with the Church and hence never really tried to start his own "school" of thinkers. Yet there were people at the time who were aware of the dangers of his thought, and I believe he was even forbidden to publish at one point (I'd have to check that, I'm not sure about it). And of course he was a Jesuit, so he probably got off the hook as simply being Jesuitical rather than pursuing his own religion...
In any case, you bring up a very interesting point, and I think there's a lot to it.