Current questions and answers regarding the map editor.

But unfortunately, when I enter the editor and click "edit script," it gives me the error shown in the screenshot and crashes. However, as soon as I delete the text file from the map archive, the editor works perfectly fine.

This is just a coincidence; the editor crashes when attempting to edit scripts for everyone with some probability. You can write scripts in Notepad and then insert them into the map file by opening it with an archiver, or you can use special programs, such as HoMM5MapScriptsEditor (I recommend it; it allows you to add text files with a single click).

But the Heroes V map editor cannot implement many things that the map editor of, say, WarCraft III can.

I haven't worked in the WarCraft editor, but the Heroes editor allows you to implement logic of any complexity thanks to Lua (much more than the visual editor of the fourth Heroes game). However, the front-end for interacting with the player is severely limited by the game's gameplay capabilities – you can only do what the developers needed and what was found in the original campaigns and maps.