Text editors are one of the few very-well specified systems. The requirements are very well known and there is plenty of information available on design and implementation. Yes, text editors are very easy to implement.
The problems come when people think it's so easy they can just jump in without doing any reading.
Hey, I'm currently in the stage where I do research to build a text editor. Would you mind linking some of this information about the design and implementation you're talking about? More interested in the UX/higher level things that the low-level code for optimizing and such.
I can't tell if you are sincere or you are trying to be passive aggressive. We've been talking about raw performance and you ask about trimmings. Also, I'm not going to do your googling for you.
I wonder if you spend 8 hours a day staring at a text editor... I recommend you make your own if it's so trivial