Freeze-calc: Select areas of cells to freeze recalculation
The workaround now is to "paste values" on top of your formulas for the biggest part of your sheet. But then you may need to copy them back. A simple freeze-unfreeze button could do the work. It would also be nice if these cells were marked somehow (e.g. with an ice-blue triangle in the bottom right corner - same as the green one for the cells with comments).