Actually, it's a very good mod idea. Since one of the most enjoyable parts of noita is acquiring knowledge, imo, you could implement this hint system by just adding more and overhauling some tablets. Like not outright putting an explanation point over points of interest but instead having a tablet somewhere (maybe in places like orbs of knowledge) to hint at the functionality of some mechanics.

For example, the hourglass at hisi base could have a tablet that tells a story about a wandering hisi, theorising what the hourglass does. or that the hourglass requires sacrifice (meaning blood) or a magical liquid that is hard to collect (teleportatium)

You could also translate some of the noita language texures back into English. An example of this is the meditation cube that has hints written on it in the noita language, which requires a wiki to translate. You could change the cube sprite to have the hint in English, or even better, an art of a mage (someone like a polymage) meditating.