I agree with you. In the Netherlands we have a lot of 30km roads inside towns which are also tagged accordingly (unclassified). When I create routes inside towns I often get big detours, so I have them enabled as well.
Enabling small local roads is no good idea everywhere. I did it last year onCrete and had some interesting adventures leaded through several villages #-o
I am looking forward to have separate OSM and TomTom vehicle profiles, so it will match 1:1 to the map source ... but the progress is delayed (there is even not total agreement if it is good idea to split it).