Item suggestion: AD Zhonya's Hourglass & AP Thornmail

Greetings fellow summoners,

A time ago Riot Games put a new item in the game called: Luden's Echo . That AP shiv item so that AP champions like Veigar have a statik shiv effect like the AD champions when they buy Statik Shiv . So my friend and I thought why isn't there then a Zhonya's Hourglass for AD champs or a Thornmail that counters magic damage instead of basic attacks from enemy champions. If these items are in the game the build style would be more mirrored and probably more balanced so that both sides (AD & AP) have the same advantidge. The AP Thornmail sounds probably OP if the damage sends 30% back if the source of damage deals over 1000 magic damage ex. Veigar's [R]. So I think that there should be a limit then like max 150 magic damage or more send back to the source (choice is up to Riot). For the AD Hourglass it is grazy if it gives you 120 AD instantly if you bought the item. so I think that the amount then should be reduced to 70 or 80 and gives you a bit higher amount of Magic Resist or Armor (choice is up to Riot). I hope that you'll like these suggestions fellow summoners.