These are some of my favourites:
The Inner Light
Chain of Command
Sins of the Father
The Most Toys
The Offspring
I mean there are loads of bangers in the whole series and I think it just gets better over time in general but those are some ones that come to mind.
Yeah there is a lot of story in there and the whole episode feels gritty. Patrick Stewarts acting is solid from season 2 onwards IMO, but I am quite biased