In an interview with Edge magazine (issue 288), Dark Souls creator Hidetaka Miyazaki has stated that there are no more secrets to be found, in terms of items and Easter eggs, at least. Of course it had to happen at some point, but I don't think I wanted confirmation that the well has run dry. So much of Dark Souls' allure is in not knowing and attributing significance where there might not be any.
However, it's nice to see Miyazaki acknowledging the influence that the community's theorising has had on Dark Souls and the importance of the holes in design that have been filled by wild speculation, even if he's keen to remove some of the roughness from Dark Souls 3.
"Dark Souls is in some ways an incomplete game," Miyazaki says, "and I like to think that it has been completed by players, by their discoveries, as they moved along. I’d love to say that the nature of this incompleteness was completely deliberate, but it is both deliberate and by accident, in different ways."