I came across this sentence in 雁:
一体お玉の持っている悔やしいと云う概念には、世を怨み人を恨む意味が甚だ薄い。
My understanding is that 恨, unlike 怨, can convey not only resentment but also regret. My questions are the following:
(1) Does 恨 carry anything like this connotation in the context of "人を恨む"? Does "人を恨む" express something less aggressive than "人を怨む"?
(2) Are two different kanji for うらむ used here simply to avoid repeating kanji within a short span of text? If so, does this practice generally nullify the particular connotations of the homophonic kanji in question? For example, if 恨 were used purely to avoid repetition, could it ever connote regret, or would it only express resentment?