Some interesting thoughts and predictions and a few things I'd like to respond to:
1. Dany being generally awful/villainous: I think the characterization that she's selfish and a poor decision maker is unfair. From the start, she was thrust into being 'queen' (traded as a sex slave for an army) and with few exceptions, is where she is and how she is because of bad advice. She didn't kill Khal Drogo - he was wounded in battle and near death after attacking Khal Ogo (and was probably going to die) when Dany bartered his horse in exchange for magic to cure him. Remember, at this time she's a teenager who's lived in exile most of her life. Unfortunately, we know what happened to Khal as a result of the 'magic' - it was a curse, he died, and their unborn child died too. Dany was ready to give it all up and kill herself (by laying on Khal's burning body) when it was revealed that fire couldn't hurt her. Since then, her piddling around Mereen was mostly at the advice of Jorah, and re-opening the gladiator pits was at the advice of either Tyrion or Varys (two really smart people who have made astronomically dumb decisions with Dany). Tyrion also suggested she negotiate with the slavers (who then attacked them), and whoever told her to split her army to attack King's Landing, Casterly Rock, and the Iron Fleet were idiots. Dany takes good advice when she gets it (see last night's episode with Jorah). And holding Jon Snow hostage makes sense - she has no reason to trust him (and has grown up believing nearly anyone from any respectable House would rather see her dead - especially the bastard son of Ned Stark, who helped overthrow her father, and who also approved a hit on her life when he learned where she was) but in the end, she does.
Disagree. Khal Drogo only fought Ogo because she arrogantly tried to take his collection of slaves away from him. She commandeered them from him and then pulled the I'm the Khaleesi card. Drogo took her side, Ogo challenged him and cut him. Cut got infected and he was done before the black magic. Had she been more diplomatic and less arrogant, Drogo lives. Tyrion made the decision to negotiate with the slavers by himself, after she rode away on her dragon. She had no reason to hold Snow, he came alone asking only for help. Tyrion advised her that he trusted John Snow. She demanded fealty and held him, giving in when he showed her the cave drawings and dragon glass. Certainly agree on spitting the army. It does seem as though all too often she follows the bad advice she's given and mostly ignores the good advice.
To me she says the right things in discussions with her council but otherwise her actions and words betray her and come across as arrogant and power hungry. At least with Cersei her treachery is out in the open. Dany's character is well written though and I do love to despise her, which is what I think they're trying to push the viewer towards.