Why is thornmail not on twisted treeline?

It's one of the items they considered would be, I guess, Toxic for the smaller, skirmish based map rather than full on 3v3's all the time. Rammus still has his reflection passive, but they are also missing Essence Reaver on TT. Which is strange, considering we have Sanguine Blade but that doesn't replace E.R.

I just find it extreamly annoying. At the end of the game champs like Khalistan and vaybe have so much peel and mobility that you can't cc them long enough to kill them.