For me, it's the opposite - love Titanic, like Avatar. I saw Titanic three times in theaters, but have no desire to pay to watch Avatar a second time. Avatar's most powerful theme is also love - love your planet and those who share it with you. There's no doubt that Avatar is a groundbreaking visual spectacle, but although its message was intended to be deep and applicable to the current goings on, the true feel of depth was somehow lacking. I concur with xJadedx and yittz's comments.
James Horner suffered a lapse in creativity? Titanic's soundtrack is better.
I thought of Michael Jackson's "Earth Song" while watching Avatar.