The Orion is overrated and a memetic trap.
It's like propaganda, good and simple in appearance, wrong and complex behind the scenes and you can't get rid of it because simpletons think it's awesome.
This is a drive that cannot afford to fail even once because its failures mode are all horrible.
you simply cannot use it to take off if it fly over anything of importance,
you cannot afford to lose prototypes during take-off and landing one will require minor miracle,
all the complexity you believe to have escaped you'll get it trying to produce and use the finely shaped bombs, like trying to build a watch using only a big hammer.
you cannot use it in any important orbit because its engine will generate debris,
it can hardly be throttled for fine maneuver or used near anything else,
it cannot be built with much redundancy because its starting mass and shape are big,
the only fuel it can use require a long supply chain, so it will be from Earth.
If you want a better meme, look up the Sea Dragon. It have less problem.