It really dosn't seem to matter what PD do re updates, there will always be a group of people who are dissatisfied with the content. Personally I am a "car" guy so all the cars that have arrived I have appreciation for be they road or race. I do believe that that people let their own interpretation of what sport actually means along with their own expectations of what "sport" means are what's letting them down not PD.
If the game was called GT FIA Race then I think you could make the arguement that PD have not delivered. AC Competizione is probabably the best example of this it is, does what it says on the tin. strictly racing, cars and tracks. GT sport covers a wider span of sport like motor racing in general. One make, GT3 & 4, supersports, various formula, karting, improved production, rally ect. all of which we have models that are available. PD could just implement things a bit better re grouping ect of this.
We have a game that has the most important real race tracks. Nurbergring, Bathurst, Le Mans & Spa Franchorchamps (upcoming) while YOU may not like some of these there is no denying their importance in motorsport. Also we have Interlagos, Monza, Suzuka, Brands Hatch, Circuit de Barcelona-Catalunya, Fuji, Red Bull Ring and Autopolis as well all Fantastic tracks that have their place in motorsport. We also have a nice selection of cars to match in various catagories as well. The sounds are all greatly improved and the visual appearance is pretty damn great. The only thing really lacking is proper groupings, a sharper AI and custom championships that would really give the game a fresh look and feel.
One of the most amusing things on these forums is how may pass their opinions as facts or as the veiws of the community as a whole and then get butthurt when called out upon this - so thanks for that.