Otto believes that he's a Tywin, but he is actually more of a Baelish. And that will surely become his downfall which the MC might speed up, if he plays his cards right. Otto is knowledgeable but he isn't wise just like Littlefinger. He is so shortsightedly ruthless and power-hungry. He overestimates his intellect believing he’s smarter than everybody else which is his weakness and the SI knows it.
I don't understand how Otto stayed so long as the Hand of the Hand, given that he's not a good politician. Is that what he was counting on by accusing Maegor himself before a king who did not object to Maegor's actions? Doesn't this degenerate understand that after the death of Viserys, a war may begin and Maegor will want to take revenge by roasting him on dragon fire or massacring him in Hightower?
Actually question for the author: Could Maegor possibly try and use his runes to heal the King? Obviously not the arm back but it could possibly help him recover his health. Maegor did offer trying to heal his mother when she fell from her horse. Probably won't happen, cause we need dragon dance drama *cough*