Before an admin shuts this down as Idea Delivered, please note this is NOT the same idea as this one.
Tech Sup has now ironed out the problem which was resulting in my termbase having the old appearance in MT 2017. I now have the new appearance with the blue and green boxes but the edit path in the new UI is as unintuitive as in the old one.
Currently when I create a new entry, it does move the cursor into to Soure field automatically. Once I've added a new Source Term, I can either use the Tick or Enter. Either will add the new item but stop there. Same goes for adding Target Terms, Enter or Tick adds, but stops there. I've also noticed that F12 no longer is a Save shortcut.
Especially in Target, this is still unproductive. A much more productive path would be (given that virtually all languages have more morphology than English):
1. Type the Source or Target Term
2. Use Tick to save and close entry.
3. Use Enter to save and automatically open next Source/Target Term field.
4 Continue until user uses Tick or F12 (do bring that back...)