User blog comment:Zilla4444/The Sheen/Trinty Force Dilemma/@comment-71.136.48.108-20120627015838/@comment-74.240.127.28-20120627035646

Then I think you are missing his entire point. I think the author has an issue with Sheen's passive on AP champions as it does physical damage based on attack damage. For those AP champions to make use of Sheen, they are kinda of forced to build it into a Lich Bane maybe earlier then they might have wanted so the author wrote on this topic to offer alternatives that would help them make use of Sheen in the early game.

TL;DR: Trinity Force is great on a lot of AD champions but Sheen and Lich Bane is very situational on AP champs.