This is purely speculation on my part, but I feel like Rockstar Leeds is considered the runt of the litter, just based on the relatively small success of their titles. CW was theirs, and despite fantastic ratings, it tanked. And though the "Stories" games sold pretty well, I suspect they sold less than Rockstar had been hoping.
So, sadly, I'd bet their designers are not even invited to the grown-up table for discussion on the main GTA games.
OTOH, Rockstar San Diego managed to really knock one out of the park with RDR, and it's almost certain they are contributing to GTA V if they were indeed even working on LA Noire.
I sure would like the ability to listen for random gang attacks to foil, muggings and rapes to stop... He'll, I'd even be happy putting out fires and delivering noodles again.
Even if it distracts from the Oscar-worthy story...