In my limited experience, a desirable Arab will have a long, flowy, powerful stride. You can't cover much ground if their lope stride is 4 feet long LOL.
She may not lope the same way under saddle, I don't know, I would have to either ride her or see video but if that is just how her lope is, I would keep looking.
I broke in a gray mare last summer that loped exactly like that. During the initial stages of training, I literally could not lope her for more than a couple of minutes at a time simply because I didn't have the stamina. She would literally beat me to the point that I would have to stop and sit still to catch my breath. She did eventually get better with more training and more miles, but it still wasn't nice. She went from impossible to barely tolerable, but it was never enjoyable.