So baelish seems to have taken the reigns at the vale, even the old couple seem to be happy following his advice, but so far I've not seen Baelish as someone who would start a war and lead an army even if he has a really big one. He seems like the guy who stays out of trouble and keeps himself in the safe, so I am really confused about what he's planning.. what was the motive behind killing Lysa. Also, I fear a bit for Sansa now, Baelish is the only one she can trust at the moment, which is a very dangerous thing as his father found out. I don't see her out-witting him or something so I fear when the time comes Baelish would get rid of her. One reason that I can see is Baelish banking on Tyrion being killed, and then marrying Sansa (his wife died as well so I presume he is free to do that) and ending up being the warden of the north. Is this pointing towards a battle between The Vale and Boltons, specially as they spent time showing us that now anyone who thinks of taking up the north has to battle them? Possibly, but tough to say.
Also looks like Arya again came really close to meeting her family member but won't. That scene ended abruptly, even if Lysa is dead I don't see any sense in them taking a U turn after coming this far. Where else is there for them to go?