Just to weigh in;
I really enjoyed the Monkey Island Special Edition system where you pressed F10 (I think) and it toggled between the graphics and sound of the original release and the modern remake.
I really, really love seeing comparisons between things- photos in the same location through the years, alternate timeline re-imaginings of fictional places I know, even remakes and original releases. Having one button to toggle between the two at will, without going through a menu or playing a separate "Classic Mode" was amazing- the F10 key was pressed more times while playing MISE 1 and 2 than literally any other time I've used the computer. I probably pressed it several hundred times through the course of each game- at least once per screen, sometimes mid-conversation.
If it's not too much trouble, I think a similar system for DoTT would be almost mandatory. Seeing how far we've come, or seeing how things were in the golden age of adventure games...yesss.
Other than that, I'm not sure what features would really improve the game. Improving the graphics and letting it run on newer computers pretty much seems to be it. Keep the verb system rather than a cycles-with-right-click mouse pointer, maybe make it a bit more obvious that after a point you can just drag an item onto a character's portrait to send it to them instead of having to visit the John-o-tron every time, seems fine enough.