It looks a bit difficult to me. Lets look at the "print"-command. Why must I choose "message" or "expression"? Could not be any message handled as an expression?
Yes, any message can be handled as an expression, so if you want to type your message as an expression there's nothing stopping you - but you'd need to remember to put the quotes around it.
The message: Hello, world!
Is equivalent to the expression: "Hello, world!"
In most cases, I imagine most people will just want to print simple messages, which is why "message" is the default - I don't want people to have to worry about quotation marks. But if you switch to "expression", your message is automatically converted.
We have to do it this way, because unlike Quest 4, we don't use in-lining. In Quest 4 if you wanted to add a variable to a message, you added it by surrounding it in "#" characters. We don't do that in Quest 5 (well, it could still be added I suppose).
Hopefully you'll see it's fairly intuitive when you play around with it a bit.
And how to you want to handle fontcolour, -size or tagged text?
Fonts: Currently, you'd have to use a script command to change the font. We should probably add some XML markup to allow you to change it within a printed message, so in that case you could type the XML markup directly into the message, but I'd probably also add a "formatted text" option to the drop-down too. This would increase the size of the textbox, display formatted text, and add a formatting toolbar (using the existing Editor RichTextControl).
Tagged text: I think XML markup is not the right way to do this. I'd probably add a separate command instead of "print", to allow you to specify a dictionary to use for the drop-down list.
The "Set Variable" is only for the first call of the variable and there will be an other command for changing the values of an existing variable (like in Q4 I think)?
No, there's only one "set variable" command.
Perhaps the expression dropdown could become a bit large and overcrowded
Maybe eventually, but the design could be refined in that case, maybe to pop up a searchable tree, similar to "Add script command".