Yeah "Looking For Something" doesn't get enough love
Don't like "Trespass" nearly as much as you do but the opening lines of that one are one of my go-to earworms. And yeah, Genesis do have some good vocal melodies but the best ever? Nah, not hooky enough- "continuous flowing melodies" are all well and good but it's ultimately down to the quality of the individual melodies and Genesis has rarely delivered any that have truly impressed me (though their music has plenty of other things going for it, of course).
And what you seem to consider "continuous flowing melodies" is probably partly just the result of Gabriel adding some US soul style inflections while essentially reciting his (typically) wordy lyrics. You know that his main singing inspiration was Otis Redding, right? Ever since I found that out, I regularly notice that Pete completely sounds like a reedy-voiced Englishman trying to sound like Otis. Of course, he mostly fails but it results in something more interesting.