I forgot who I asked, but during a Zoom meeting about planning for the next aBRT routes I asked why the Nicollet and Central lines aren't combined and they said it's because the route would be too long and lead to reliability issues.
Yet, the reason the route is so long is because it's been drawn that way. A combined route could easily be drawn shorter. I'm not sure why the Central portion would need to go any further north than the Medtronic HQ, and the CHTC would otherwise be a natural stopping point. The Nicollet portion could also stop whenever you want it to, just tie it into any of the Orange Line BRT stations near American Boulevard.
The question isn't a technical one, it's one of trade-offs. I want to see a combined route, because to me, the most important thing is to have service that is balanced by bridging downtown. It doesn't make sense to cut off service halfway through the highest demand area (basically within the 494/694 loop). What is more valuable, having one aBRT line which runs through the entire high-demand travel zone, or having two aBRT lines that serve half of that zone but also serve outlying low-demand areas?
I'd want to concentrate the best service where there is the most demand. The best type of network design is a high frequency grid, not a hub and spoke.