Space bombs - are you kidding me?
Remy Redert, you're oversimplifying them unrealistically. I don't even know where to begin.
So I'll start with the fact that a couple of kilograms of iron alloy ejected from a space launcher will make a small glassed crater about a hundred miles away from the target - if you're good.
Even from 5 miles high you can't drop a dumb bomb perfectly accurately, and I'm talking about ones that make a big kaboom (to lower the margin of error) and have fins and aerodynamic shape. The atmosphere is a major wildcard.
Even bombs dropped from an airplane are NOT that simple - and yes, they come down with PLENTY of speed, enough to penetrate DEEP into concrete before blowing up, so you can really rip up a runway if you need to.
Now, let's say that we DO have a bomb with whatever it needs. You still need an orbital maneuvering system either on the bomb or on a launcher that contains the bombs.
The ~big~ reason is that you need to actually be able to change your orbital inclination so that you ~actually go over~ your target. This is a VERY fuel expensive operation, especially if you're dragging 5000 tons of bombs. This launcher will need to be huuuuuuge. You're only going to be able to afford a few inclination changes even if you made the thing an epic god of satellites. This thing will need to be far, far bigger than the space station to be useful.
And guess what? It'll take so LONG to maneuver it that it won't actually be any faster.
So maybe you could put the manuevering system on the bombs.
But then, why even do that? Why not just keep the bombs on the ground, and launch them into space with a ton of speed so that they accurately fall on their target thanks to the magic of math and some kind of attitude control in the warhead?
That'd be a great idea!
So great, in fact, that everyone already has this.
http://en.wikipedia.org/wiki/ICBM
You might be thinking, "But then you have to launch a rocket to space every time you want to drop a bomb!" Guess what. You STILL need to launch every ounce of this system on a rocket.
Much, much BIGGER, more expensive rockets using a lot more fuel because putting something into ORBIT is a lot more expensive than a suborbital ICBM trajectory.
So, is orbital bombing too complex? No, but it's bloody stupid.