Interesting discussion.
During the evolution of the minifig there has been steady progress intermixed with a few leaps forward that often are looked at as too progressive.
I was stunned back in 1992 when I started getting black knights with beards, and wolf pack figs with eyepatches.

I had so many figs with just smiley faces that I thought these guys were going to stick out like a sore thumb. Now the smileys are a small part of my collection. I would not want to go back to only smileys; It is much too interesting to be able to put expressions on figs faces when put into a MOC.
I have to admit that I was a bit shocked when I saw all of the custom elements on the Toy Story figs. However, I am not sure they could have pulled off that licensed theme without them. We have to remember that this line in particular is aimed at a young crowd. Childrens imaginations are a bit more limited and they need to see something familiar to be drawn to the sets. I do not think that these detailed elements are going to be the norm in the future. I think they may be used but only in licensed themes.
I think TLG has done a good job of incorporating new ideas without making older figs obsolete. When I mix my old figures with the new ones you can see a difference, but I don't think they look out of place at all.