Portal 2 was great, hell the ARG and the getting the golden potato for it is easily the most fun I have ever had playing video games ever. I'd race home from work every day to see what people had found and do any of the new challenges, and that is the last time I ever enjoyed something by Valve, but I couldn't even tell if that team actually works on games anymore at this point. Which is why I don't get this obsession with loot boxes now, at what point do you start investing your endless amounts of cash into actual game development again.
There are genres they've never really touched yet that they could knock out of the park at this point but digital CCG's are a cash grab until we hit MOBA levels of saturation again and Hearthstone remains to be the only one anyone cares about.