I was surprised actually at just how little Castiel there was in season 8, I'd heard so much about what a big year it was for Destial that I was expecting him to be in most of the episodes. I wish they could give Misha a few more episodes on his contract, it seems really arbitrary in seasons 8 and 9 (which I'm just starting on) when he keeps disappearing every few episodes. There's always some good explanation for it I suppose, but it wouldn't hurt to extent his contact to 17/18 episodes. I haven't actually counted them, maybe I'm wrong, but the moment it feels like he's barely around for half of the season, even though they want to treat him like one of the mains. Obviously there are episodes that work better with just Sam and Dean, but there are times when it feels like he's only missing for such a long stretch of time because of how the actor's contract has been worked out

It's mostly frustrating anyway, since the writers do everything in their power to show how Dean and Cas can never be a couple.

I did watch some of the early season 10 episodes (my watching of SPN is all over the place!), and I remember finding it frustrating how much Cas was separated from Dean and Sam, especially when honestly I don't find his plots with the angels all that interesting a lot of the time. I much prefer him in scenes where he gets to play off Dean and Sam, but from I understand he gets separated so much in his own subplots so that Jensen and Jared can get more time off?

I admit I've never been interested in Sam that much, so everything you mention that happened to him during season 8, I had pretty much already forgotten again...

Well his ~normal life~ plot in season 8 was pretty boring :P