You are too kind IO540. I think even my Mum would hesitate to call me a specialist. Journeyman is perhaps more accurate!
I'd say there still is a place for the SRD. It's there as a simple guide (easily carried about in printed or PDF form) and, as it says inside, the routes are not necessarily mandatory but 'are promulgated to identify optimum routeings for operators with due regard for the ATC system.' Then, once airborne, nothing is set 100% in stone and tactical requirements will dictate a certain amount of necessary flexibility with regards to what is filed and what actually happens... though they shouldn't be too far apart.