Thoughts on Reworked Thornmail from a Filthy Tank Main

Reworked] Thornmail (LCU only atm)*

Thornmail has been reworked, including new build, stats & costs, component item, and passives.

Total cost  2900g 
Builds out of [Bramble Vest + Ruby Crystal + Warden's Mail + G]

Stats & Effects:

    +250 Health
    +75 Armor
    Unique Passive - Thorns: Upon being hit by a basic attack, reflects magic damage equal to 10% of your bonus armor plus 25, inflicting Grievous Wounds on the attacker for 1 second. 

    Unique Passive - Cold Steel: When hit by basic attacks, reduce attacker's attack speed by 15% for 1 second.

For anyone wondering, this is Bramble Vest:

[NEW] Bramble Vest (LCU only atm)*

Builds into Thornmail.
Total Cost: 900g.
Recipe: [Cloth Armor + Cloth Armor + G]
Stats & Effects:
    +35 Armor.
    Unique Passive - Thorns: Upon being hit by a basic attack, reflects 25 magic damage, inflicting Grievous Wounds on the attacker for 1 second.

So, what is the new Thornmail like? Well, it's tentative, for starters. That's depressing, but hopefully we'll get some more context soon.

Thornmail has lost 25 armor, gained 250 health, and added 700 cost along with the Cold Steel passive.

The damage returned has been significantly lowered, from 15% of pre-mitigation damage dealt to 25 base plus 10% of your bonus armor. For those of you who are less math-oriented, a full crit Caitlyn Headshot could easily exceed 1000 damage pre-mitigation, so you could have upwards of 150 base damage on your Thornmail return.

In exchange, Thornmail now applies Grievous Wounds. This is the big thing that a lot of people have been requesting for a long time. So what do I think about this? I think Grievous Wounds is largely too broad of an application for the effect that people actually want.

What people want is they want Thornmail to actually damage through lifesteal. What Grievous Wounds does is lower lifesteal but not negate it, and punish a lot of other champions that don't deserve it. Darius should not lose his giant Q heal because he W'd the wrong person beforehand. Renekton jumping in for a quick W Q shouldn't get punished either.

Generally, melee champions have very specific combo rotations that require a lot of muscle memory and are dependent on certain abilities that heal them for quite a lot.

So I don't think reducing lifesteal by 40% is good enough, and I don't think punishing melee champions for choosing the wrong target is a good thing either.

I think that Thornmail should simply have its own passive: Unique Passive - Thorns: Upon being hit by a basic attack, reflect 25 magic damage plus 10% of your bonus armor. The target gains a stack of Thorns, which reduces the target's lifesteal by 8% for 3 seconds. This effect can stack up to 12 times.

There, now you punish lifestealers who focus you effectively without screwing over melee champions who desperately need their healing.