Oh wow! Yes, DoF is another effect that is best served during appropriate circumstances for guiding the eye. I wasn't aware that it had performance saving benefits. Shame we never got that in the ME trilogy (then again, DoF effects generally amounted to Gaussian blur on last gen HW).
Talking about RE2 and SSS, I am reminded of GoW, another game where it is variable but it does show up prominently more often than not (I tend to go for close ups of the models) and on the flip side JFO (at least on consoles) has one of the worse implementation of how skin to reacts to light.
For example-
Real time cinematics:
Gameplay when it's good:
And when it goes pear shaped:
It's more than just SSS though, I can't put my finger on it but it's the way the skin reacts to lighting as well as character shadowing that looks, "off". And it's not specific to this game either. I have seen it in almost every game. Makes me wonder if ray tracing would be of help here.