1) Last Hits
So they're long overdue for a refactor that tries to assure that if they hit the creature on the same frame that the creature died, they get the last hit. I don't know how easy this is as there still might be some tricky guesswork and timing issues involved even with the new tools.
2) Growling
Rangers should "growl" when in a shape changed form. It gives them a special speech bubble, the text log shows up as "growls" instead of "says", and it sometimes makes a growling sound. This is probably a trivial change.
3) Tracking
Tracking could probably be improved in a few ways, but the most important is giving an actual reason for training to a longer duration. Some possible improvements include automatically switching to another monster of the same type if the monster you are tracking dies and/or automatically finding a new target whenever you or the monster switches snells.