I tried some painting recently, and it was harder than I expected. I painted a thin white sheet of paper with a mixture of blue and white acrylics, only on one side.
These were the disadvantages I saw:
-It's difficult to get the same amount and mixture of color on on different spots of the paper.
-You'll need some equipment, I had the use a small brush and it took a long time to paint a 35cm square.
-I also needed more color than I wanted to use, and the color still didn't turn out the way I imagined.
-When a thin paper is painted on only one side you'll see the color shine trough on the other side.
-Also, if you try the put color into MC-solution the color will be much weaker.
-Paper might get wrinkles when drying
But painting is not only bad

:
-Some paints can help stiffen soft paper.
-It doesn't add too much thickness to the paper.
-Any color combination is possible, painting by hand gives the paper a unique pattern.
My problem with gluing is that I have some bleeding papers, when I try to work wit MC it becomes a mess... I'm not sure which of the methodes I prefer
so, those were my thoughts, I think making a paper with the perfect color needs some practice.