Buff Thornmail

Today I've played Nasus on top, as usualy it was tank build (Frozen Heatrt, Randuin's Omen...) and Thornmail. I've had approx. 360 armor and I was with 7/2/... score. Once, in 1 vs. 1 fight with enemy ADC I saw that all this armor deals.... Nothing - it was useless. Lets do some calculations: At start Nasus have 25 armor. As we know, Thornmail returns magic damage equal to 25% of ours bonus armor - soo we get 360 - 25 = 335 bonus armor. 25% of 335 = 83.75 magic damage. In a second part of Thornmail's passive said, that it also returns 15% of damage of attacker's AA. Lets imagine, if enemy deals 400 damage with AA, 15% of it will be equal to 60.

Now we got: 25% of BArm + 15% of AAdmg = 83.75 + 60 = 143.75 magick damage returned by Thornmail in this case.

I don't want to say that Thornmail is a bad item - I want to say, that it is good at early game and a bit useless in late game. You may ask me "What? Thornmail is useless in late? Are you an !diot? #Omg #l2p #stayinbronze". I'll answer - the problem is BotRK, this item deals 6% of your current health on hit. Again you may ask me "All this time all was OK, and now you say that BotRK is broken and Thornmail useless? OMG noob, realy???". Yes, it is - the problem of BotRK is lifesteal, which can proc on this 6% of enemy's current health (relatively recent changes from the end of 5-th season).

Now when you will be attacked by an enemy ADC, he can successfully refund his HP with lifesteal (BotRK + BT, Mercurial Scimitar or Death's Dance ) because this lifesteal (and MR of Mercurial Scimitar) can in most of cases cover damage returned with Thornmail.

In the end I want to sai again, that Thornmail (in his current state) is usefull only in early game or on specific champions like Rammus or Taric. In late game - it's a wasting of 2350 gold.

(Sorry if I did some grammatic mistakes - english is not my native language)