What is the hardest playthrough in the game?

Thus far, my choice is Maelys. Whenever i play as him i always fail to take the iron throne. Even if me and my allies control all of essos, i never have enough soldiers.

Now that dragons are in the game i thought it would be much easier, but no. Even if you manage to get a dragon by sacrificing your son, the dragon will not get big enough to do pretty much anything in battle.

There is also the fact that everyone (even his allies) hates Maelys because of his negative traits, which is so annoying.