Currently when you stop watching a show you have three options:
Leave it in your watch list and ignore it
“Hide” it which keeps the unwatched episodes in your statistics
Remove the show completely which removes watched episodes from your statistics
Having a “dropped” option would allow statistics to be up to date while not showing episodes you have no intention of watching in your unwatched statistics.
There is a fourth option. You can skip episodes or seasons. However, skipped episodes are often not synchronized correctly between new devices. And you always have to add episodes to series that are still running.
Yeah, the need for constant maintenance on a show you’re not even watching anymore makes that a less than workable alternative IMHO. (I stopped watching Greys Anatomy in like 2011, I don’t even want to THINK about how many times it would’ve popped back up in SeriesGuide with new episodes since then.)
Fortunately, I’ve always been in the habit of Hiding any show I’m not actively following, whether completed or abandoned. Just to keep my “Added” list tidy & focused on what to watch now or in the future.
But I agree with the suggestion here, a “Dropped” flag would make sense to have. (Bonus points if you can configure whether Dropped series should be visible by default, in the “Added” list.)