It's still a yellowish light for me as well. I was able to drive my smaller Gloucester Terminal Electric route for hours the other night without any hiccups other than those caused by my own inept driving skills.I'm using build 125920. It's too soon to give the green light on this series of updates which fixes the confused AI drivers: stopping, backup, and other random adventures. But I will at this point at least show a yellow light. AI driven trains seem to be behaving much better and for the most part go where you want them to go. A few hiccups, but a few extra track marks seem to fix these issues to AI's satisfaction.
Still not getting the bulk replace to work properly. For example, when I tried to replace some speed boards it also replaced some signals with speed boards. Perhaps I don't understand the fine points in making bulk replace work.
Bulk update works okay for me for large areas but is still broken for selected areas in Classic Surveyor. I tried the new replace assets method in Surveyor 2.0 and it worked okay for me. I think you may have had some technical difficulties.