Problem: Reviewer might think: “Do they know their field? What do they know anyway?” Better: Describe what you did to validate the statement. “We performed a literature search via abc / We searched in database abc with keywords xyz and found …”
Problem: They express too much uncertainty. Better: Be clear and forward looking. “We will…”, “Our goal is…”
Problem: The reviewer might not agree with your statement. It will put them off. Better: Describe your idea/science/impact and the context and let the reviewer decide on its merits.
Problem: They are just fill words and do not add much. Better: Avoid them.