Hi there, I am a big fan of these AGS games and although I haven't yet made the jump to trying to make my own, I'm a long time game player and always have lots of ideas as to how games can be improved.
One thing I have thought of that could be used in any game is a log of the most recent dialogue or other text the game has presented to you. The reason I say this is if I accidentally click the mouse and skip some onscreen text, a lot of the time the only way I can read it again would be to reload an earlier game or restart. Because of this I find myself saving my games very regularly just in case I miss dialogue.
It could be as little as the last 1 or 2 lines of dialogue/text, it could be integrated as a notebook or just as the character's memory, it wouldn't seem out of place in any game I reckon.
Thanks for reading! I have other little ideas like this that I think could become a part of each game as standard, often things I see in one game that I think should really be in every game. I'm happy to elaborate if anyone is interested!
Thank you all for the great games you make, they go a long way to livening up my life.