I don't mean to disappoint you, but apart from the machines, which are a prime example of really really really bad design, none of the things you've described are a quirk of the Sofia Metro.

While I agree with all of your points, people should stand on the right on escalators, and they would damn well stand on the side of doors to speed everything up, even here, in neat-queue-on-the-bus-stop England people seem to use the metro in very much the same manner as you describe. Nobody stays right on escalators and people rush in as soon as doors open, tough luck if you want to get out. 

Except in London, but you would be stampled to death by the people coming out of the underground cars and rushing up the elevators, so I think sticking to the 'rules' is more of a survival thing there than common sense or courtesy.

So my point is, what you are describing is annoying as **** and the equivalent getting in and out of buses in Sofia has on some occasions made me homicidal, but, alas, it is not a Sofia thing, nor even a relatively new Metro thing. It's just people being plain stupid and inconsiderate, with no threat of a stampede to make them think twice.