more impact I think if you stick with similar colors for the large blocks say all green on bottom right.. growing upwards to the blues then the reds in top side but slightly not all diagonally place you know.. a couple bumped in each section .. use the smaller blocks for the seperations diagonal lines.. so you get a gentle swerve up to the next color like a line from bottom left moving up one then three blocks at a time to switch to then next color. I think when its said and one you doing to really like the eye popping quality of this quilt. I would consider one more shade of each block color like a slightly lighter version of the blues etc.. so you add a little pop? not a whole bunch just a few of each so the color gradiates upwards?