My opinion that if Simon's Quest is remade, they should make it extremely different from the other games in the series, just like CV2 was different from the original CV.
First of all, I want it either in full 3D or made in Diablo-like graphics (where the view is from above). Second of all, they should give up on the RPG elements to increase the adventure (quest) game elements in the game. The special item you find and buy throughout the game (whip upgrades, holy water, garlic, etc.) would have much more of a value if you won't go up levels all the time.
Also make it much creepier, like a total silent hill atmosphere, with day-night transitions that make your blood freeze. of course, I would like much more cut scenes that would assist in understanding the story, as well as set the atmosphere. For example, I want the first night in the game to occur shortly while you are leaving the first town, and then there would be a cut scene with the sun setting in the sky, and the townspeople rushing into their houses, doors shutting, all out a feeling of fear and as Simon watches the moon rising in the sky, he would say "What a terrible night to have a curse".
The night should be fearsome, with ghouls appearing from the darkness, skeletons rising from the cold ground, and all out to attack you. As for the castles in the game, they should be views of absolute horror, with tortured men, sounds of women screaming, growls, etc. All throughout the game, you would meet in the most unexpected places people/creatures who would assist you- weird salesmen, dying warriors who would hand you valuable items, witches who would whisper you secrets.
Oh, and did I mention this remake has ought to be M+? Yeah.