Is this is the one? This is gorgeous. I like balanced things & this is bargello appeals to me more than a lot of them. I agree either enlarge all the pieces, &/or add borders. You could even do a bargello border for your enlargement, keeping the scale for the center as the pattern.
A measurement I have for a queen mattress is 60 x 80 inches. Your pattern is 50 x 57.5 inches. To just fit the top of the bed, you will need another 10 inches across the top and 22.5 inches in length. Now you have to add overhang to cover the mattress and a turn under part for the pillows. Lots of decisions to make. I would leave the pattern as is, then add background to upsize the quilt to the queen size bed top putting the extra length on the top. In other words, when you add 5 inches to each side to get to queen size, only add 5 inches on the bottom, then put the extra 18.5 inches on the top. This would center the bargello and leave it as the focus. When I got to the drop, I would probably do border rows with the colors in order and increasing in width to get the look you want.