What makes no sense to me is Jon Snow. If he was in love with Dany and didn't want the throne he would've respected Dany's advise to not tell anyone about his lineage, and he wouldn't suddenly be unable to show her affection. The fact they are related is a little weird but they didn't grow up as family and their parents aren't even alive.
IMO, the rampage Dany went on is somewhat believable given her history and feeling that she's being betrayed by Jon, but I simply can't believe Jon would behave as he has, it's just too stupid and short-sighted, and completely disregards his feelings for Dany and the experience he has gained over the years. He's just not that naive anymore, and he's not stupid.
I also don't think Varys is that stupid either, his actions contributed to Dany's feelings of betrayal and thus contributed to the murderous rampage he was willing to give his life to avoid. IMO he'd see that as a possibility and should have/would have remained faithful to Dany and attempted to influence her to not destroy all of King's Landing.
It all makes me care less about how it'll end.
I did like Dany's tactics for avoiding the scorpion's arrows though, they simply can't change aim fast enough to track a moving dragon that understands their weakness. They got a few shots off, but after Dany got behind the iron fleet they were history and the low-to-high maneuver approaching the castle walls allowed her to get behind them... after that they had no chance.