Absolutely nothing is wrong with the stock rims. They look great.
What is wrong with this scenario is putting tires with a 255 mm width on those stock rims. The problem does not arise because of the diameter of the new tire size (it is arguably as close to stock as you are going to get), the problem arises because of the width of the new tire. The new tire width would cause excessive overhang when mounted on 2000 stock rims causing premature sidewall damage and, quite possibly, worse handling. Traction and braking will improve, because the area of contact is greater, but handling will suffer. Ití* a judgement call really. For me, I am going to stick to the stock tire size.