Sometimes when kits are too large, it is difficult for the doe to deliver them, and when the first one gets stuck, the others in line die while they're waiting. In my experience overly-large kits can result from either the doe being overweight, or the litter being so small that the kits grow bigger than normal.
Even if they were not too large, if it was the doe's first litter, it may have taken her body a little too long to figure out how to push the kits out. There's a good chance that next time everything will work perfectly.
If the doe looks and acts healthy, it should not be a problem to rebreed her. I would encourage you to first make sure she's not fat, though, since overweight does can have all kinds of problems conceiving and kindling. Feel around her shoulders; fat rabbits will be flabby in that area, if they're really fat you can even feel the fat lumps there. Especially if she's a mini lop, she should be built like a brick, with no flabbiness. Don't worry about loose skin, or a flap of skin/fur around the base of her hindquarters, like a skirt; those are pretty typical of lops and don't necessarily mean they're fat.
If the doe had vaccinations recently that might possibly factor into her difficulty kindling, depending on which shots she got and when.
Breeding rabbits is not considered controversial at all on this forum. Many or even most of those posting here are breeders or intend to become breeders. They're also as non-judgemental a group as you'll find.
