First of all very pleased with the mod. It seems to catch and avoid a lot of the usual pitfalls that happen with LTN like instant delivery on half built stations and deliveries to the wrong station due to renaming during delivery. Issues also seems to stay localized. Very few trains ever reached the depot with remaining cargo. With LTN more than once we had to shut down train networks to clean remaining cargo since issues spread due to unloading at the wrong station. Performance also seemed to hold up, even in our 1-1 ant train hell hole.
In terms of issues/improvements I already passed along the feedback about the global locked slots. Other thing I got was the wagon controller blocking unfiltered slots as an option on the combinator. Otherwise most issues was people getting used to the mod and forgetting to set train limits on the stations.
Map is still up for a few days under Redmew - K2BZ
if you want to check it out. I plan to use the mod again and put it through the ultimate test of PyAE. :)
edit: Just as I was done I got reminded of another feature request: Some form of tracking for requests which cannot be fulfilled due to lack of items. Essentially its about production bottleneck detection. Not sure if you have something that you could expose easily in the form of a muteable error message.