There's so many reasons why this season could've been shorter (my theory was that the writers were trying to write a transitional phase for everyone, which is usually very long and tedious or short and sweet to the point) and I don't think we're justified in complaining about that so long as we got set of really good episodes. I'd rather a few good episodes than loads of slow-paced ones.

The spotlight has been on Mike as the leader since day one. After two seasons of establishing his character, it was appropriate of them to take a step back from him, and focus on others. Hopper was all moody because he probably has PTSD from all that crazy shit he just went through. As someone with PTSD, it's not all flashbacks and all that other shit they show on TV. It's also being moody and resistant to change.