How about both lines serving both stations at Sheppard and STC? That way, those who are heading east on Sheppard as far east as possible (McCowan), those who want to go to STC will not need to transfer, and the line can easily extend east on Ellesmere if needed. The potential for cross-platform...
Stouffville Line Service changes start October 14
Looks like they are adding 3 mins to each trip, shifting the schedule a bit, reducing delays caused by the constructions along the Stouffville Line.