It's not a good idea. Other than the mine tunnel that actually drops into the bottom of the map, it forces the cart to pass by RED's spawn right after the first control point. This makes it difficult to push past the chokepoints at the first point, as well as push up the hill to the second point, without spawncamping. Afterward, it becomes a straight shot to the end for BLU because RED has a longer walk time to the final point.
Attack/defend maps shouldn't give the same advantages to an offensive team that are given by 5CP maps. Eventually you need to increase the difficulty of the stage.