It sounds to me like there wasn't clear communication between you and the maker of this quilt. I agree with Watson58 and Lindaschipper that even though this quilt wasn't what you envisioned it is very nicely done and highlights those beautiful embroidery blocks very nicely. I too would leave it as is. I suspect she had reasons for making some of the design choices she did and I think the quilt is really appealing. For example, the embroidered blocks look beautifully centered and not swimming in a sea of white. Had she left the blocks at 12" I really think the embroidery would have been diminished swimming in such a large field of white all around them. As they are now, they look perfectly centered in the blocks. I suspect the checkerboard layout was simply poor communication. If you handed her the green and said "I want this between each block" it can easily be interpreted as checkerboard instead of sashing strips.
If you remove the border and attach something different it will be very difficult to line up the end to end quilting design used, so will need to be quilted differently. I would definitely discuss this with your quilter as a similar situation is likely to arise if you don't have clear lines of communication. I would recommend you find pictures on the internet to show her what you want if there is a next time. Also learn quilting terms so you are both speaking the same "language". Strips between blocks are called sashing, those arrow triangle things are called hourglass blocks and from what I can see they are very well done. Size matters so be very specific about size, both the finished size and sizes of elements. Like saying "I want 2 inch finished size sashing strips between the blocks with no cornerstones, I want a 6" finished size border to go around the completed quilt, I want the quilt to finish at 72 x 82". And stress that any design decisions cannot be made unilaterally. She must discuss with you.
I am sorry you are so disappointed with the outcome but the quilt really is very nice.