Whose smart idea was it at google to take your google store wishlist and make it the google TV watchlist? doesn't matter just matters that it seems like a really stupid thing to do.
So I can't actually now create a watchlist of things I own and want to watch to easily access them and be able to quickly add and remove what I want to watch next because on Google Play you can't add stuff to the wishlist if you already own it. Plus on the Google TV (and I may be wrong here but I've not found it yet) you can't manually add stuff to the watchlist it just pulls over your google play store wishlist.
Not disagreeing with you, but I'm more conflicted than you. I can absolutely understand the utility of having them separate. On the other hand, I actually have a fairly large library of movies I've purchased from Google plus I use Google TV streaming devices. My wish list/watch list is fairly extensive as I'm interested in lots of niche content. It is useful for me to scroll through a single list to find out if the content I'm interested in is available in any form. In that regard the current set-up is most efficient for me. One list of every title I'm interested in with options to watch on various services as well as purchasing options from Google. Just my. 02
Edit: I forgot to address your comments about using a watch list for content you already own. I've had no issue with just navigating to my library but I get your point. I just don't personally see value (for me) in building that type of list. I have a massive Plex library where I can see what you propose being useful, but I've got fewer than 100 movies on Google (which in fairness is pretty large IMHO) and the need to group them somehow doesn't strike me as necessary for my use case. But everybody has different needs so I can understand your point.