User blog comment:NicknameMy/Rework for Tiamat, new tier 3 tiamat/@comment-69.141.8.150-20120401203448

tiamet leads to uncontrolled pushing of your lane, this is the reason why it isn't good.

It's not stats, how powerful or weak you consider the unique passive, or that it doesn't build into any legendary item. it turns last hitting into unchecked pushing and that's simply poor gameplay.