NR's plan at one time was to migrate the Worcester area into the West Midlands SCC when it was resignalled, also transferring it from Western to LNW Route.
The resignalling of the Midland main line from Birmingham has already seen Blackwell-Tewkesbury transferred to WMSSC, and the Worcester was to be a subsequent phase.
That would make the route from Hartlebury via Droitwich and Worcester to Norton/Abbotswood Jns part of the West Midlands setup, which would also include stretches of the Cotswold and Malvern routes to interfaces with Didcot/Cardiff ROCs.
However it's all in abeyance as priorities are (as always) elsewhere.
Same as Shrewsbury and the Marches route really.
It'll probably be ERTMS-time when NR finds it needs to resignal these areas.
Going back to pre-grouping, the area was not entirely a GWR fiefdom.
The Midland Railway had joint ownership with the GWR of Worcester Shrub Hill station, owned the Malvern-Tewkesbury line and had running powers over the Worcester and Malvern routes to reach its network beyond Hereford into South Wales.