nightstalker can still be what you expected him to be, it just depends on whether you managed to get a lot of kills in the first night to transition as a core and snowball from there.
Actually, Nightstalker was considered a pretty good utility mid carry if you knew how to play him from at least 2013-2015. I don't know much about the periods before or after that, but during that time he was seen as powerful and could snowball hard if he got ahead in strength at all.
Once upon a time, I babysat a nightstalker and rushed him to level 6 before night came. From then on he roamed all the lanes and got fed. Of course, that was when Dota was on Warcraft 3.
I want to take issue with your previous rant, Jo: I think Valve's focus is better than Blizzard's. I mean, the reason I don't like Overwatch is that it's overly designed. It's got too much of a "sheen" going with it. The game looks like a gaudy Pixar movie, which is such a turn off.
