Another thing you would have is flexibility on where you built the track and when you could start service. By deciding that a giant new yard must be built at Shepard, you're forced to build 18 km of track between DT and the SE (basically the same length as the southern portion of the Red Line is today after several extensions) before you can even start service. It also means there's no money left over to go to north where more ridership and cost-savings from bus replacement are located.
If you could use existing facilities and trains, then you could have started with a 64th-Ave N to DT segment, open it and replace a bunch of buses right away. Then if more money is available, expand further SE to Shepard, and then finally expand both ends to their desired terminus and build that dream oversized maintenance/storage facility at Shepard. You have a line that doesn't take as long to start operation, is much more useful to begin with and can be incrementally extended easier.