User blog comment:MendoMan56/Raiu- The Void Wrath/@comment-26815373-20151228041746/@comment-7709681-20151228052225

I didn't want to explain myself below because I was busy with my family and wanted to keep it short. An explanation? With pleasure:

Riot was asked once about untouched iterations, such as Assassin/Support, Marksman/Support and, most prominently, Tank/Assassin. You see, Riot does like to experiment with the idea, but they simply do not dare to try one to the public due to internal failures, and see it as an implausible idea thus far: A champion, with both raw tankiness and umparallel late-game damage, should not be able to initiate/disable and assassinate by its own for himself and flee impune, as it creates a contradiction for the intended roles.
 * Despite I despise ball-of-stats champions, in this case is not much that than the extreme synergy between the in-build stats that does bother me.
 * Both flat and percentage bonus resistances, which the latest stacking with the first, along with the champion's resistance growth and other source. Only Malphite has such amount of Armor increase, and only by ranking his W (And the kit interacts with the statistic), and no champion has Magic Resist increase that big.
 * W's Passive is just bonkers, it is not much that is a convertion passive, as LivesByProxy stated properly, but rather that the convertion rate is too much which, along with the AP scalings and both the bonus health (Which, due to the convertion rate, R also grants 60 / 120 / 180 AP, not considering HP growth and other sources) and the 40% resistances' penetration from the ultimate, make it too damaging for the intended role to be healthy.
 * There's no reason to gain bonus attack speed passively when no part of the kit interacts with it.
 * The proper gameplay that the kit provides has no defined playstyle, nor does bring interacting or interesting gameplay.
 * There's not much excitement with a spammable nuke and a significant heal (With a rather uninteractive on-hit effect), specially when they are easily exploited by the stats granted by the kit.
 * Having stealth on a tank is a bad idea, even Riot has stated so, as it grants an unhealthy initiation (for the role).