Both of these are crazy quilts and both have endless numbers of various patches but when examined there are some major differences.... mainly repetition of color and shapes.. In the top quilt there are no dominant or prevailing colors to move your eye around the quilt.. On looking closely at the bottom quilt you'll notice, even though there are a myriad of colors, red and black are dominant and repeated throughout the quilt... This technique brings a cohesive element to the quilt even with the chaotic use of other colors.
The same thing makes a block pleasing. Choose your main colors (one or two). Use them in various shapes, threads. and trims throughout the block... This is a subtle thing but very important.
Here is another example of a gorgeous, modern crazy quilt done by a group. The dominant color is blue repeated in every shade possible and it is the blue repetitions that hold the eye and makes this a successful quilt. Another element of importance to be noted in this quilt is repetition of shapes....squares and spirals. In the fan quilt above it is squares and triangles.. All the shapes are fairly consistent in size and complement each other in both quilts. There is no effective repetition of shapes in the first quilt.
I ran across a vintage poster which is a good example of these same principles. There are a myriad of colors but red and black move the eye around. You might think at first there is no repetition of shape but if you look closely, be aware of how a right-angle corner is repeated over and over throughout the poster... The same design principles apply to both the quilt and the poster... I'm really hoping that you are finding all this helpful