In my humble opinion, there are several synonyms that can be used to replace this phrase. One alternative is "from my perspective" which suggests that the opinion is based on personal experience. Another option is "in my view" which conveys a sense of subjectivity. "As I see it" is also a popular replacement, implying that the speaker's perception is unique. "To my mind" is a more formal substitute that is often used in academic writing. Lastly, "in my estimation" suggests a level of careful consideration and judgment. Regardless of which phrase one chooses, it is important to remember that all opinions should be respected, regardless of how they are phrased.