You clearly haven't seen the swashbuckler. The 5e rogue is a flexible class, there are a number of of different playstyles it can use.My point iss that the 5e Rogue is a chicken. It isn't designed to be a warrior. It's main attack only triggers with advantage or a "flanker". Only one of its subclasss can fight straight up and it has literally be in a one on one duel to do it. The class stabs people in the back then runs away like a punk.
Really, no. That is not what the word "assassin" says to me, and it sounds like you are describing a swashbuckler.The Assassin isn't the best warrior. Nor a true warrior. But it can hold it's own. It doesn't poop ts pants once the guards pounce.
"Assassin" says to me a character who attacks first, kills it's target in one blow, then slips away without any fighting at all. And the 5e assassin subclass is quite good at that.