Riot, your current experiments with Thorns effects don't address its problems
Thornmail is a crap item these days because it requires too many stats to work properly. You need bonus armor for the raw damage, HP to live long enough to use it, and MPen so that your opponent doesn't negate it with a single MR item. Unfortunately, the MPen part is something tanks and juggernauts simply don't get. You basically get a WotA problem as a result.
The Thorns effect being moved to Randuin's Omen isn't going to make it work, even if the damage is doubled against crit strikes. It's still going to get neutered by MR, lifesteal,
and
.
Care to share your point of view?
is now a 1200g item that:
+
which costs 3000g:
+ 800g
?)