You must have pretty fast hardware if all of that is done in the time of a walk!
I use iTunes 12 in the latest version and am not quite sure what or if anything was better in 11?
For example, iTunes 11 has the tracks in two columns, 12 has one (which is irritating for albums with many tracks…film scores often do!). 11 picks up the colour of the album and adds it as a background to the track titles, 12 doesn’t have this feature. 11 has the album discretely to the side, 12 has it hard upfront, on the right side. And other things. I think there are several articles online that explain how 12 is inferior to 11 for those of us who just want to listen to our hard drive files, in a nice display setup, and not connect to stores or streams or whatever.