It makes sense to me
You know, at first I agreed with the OP - a wizard and fighter shouldn't be the same when it comes to martial combat. The fighter should clearly have an edge. The problem, though, is that forever the edge has only been a better +to hit modifier (whether it was BAB or lower THAC0 or whatever.) In 3.0 and 3.5, really, there wasn't much different between a fighter and anybody else, except BAB progression and maybe some feats.
But, without having my new books yet, this thought occurred to me: the fighter is now much more versatile then in previous editions. Really. Now, though a fighter has the same basic bonus to attack (based on the OP's assumptions), (s)he has many more options (as others have pointed out.) A wizard's only option when wielding a sword (assuming he or she can) is to just hit the target. A fighter, however, can take that same sword and use it to much more deadly effect. The chance to hit may indeed be the same, but the fighter's choices are vastly better than a wizard's.
In many ways, I liken this to the way clerics were changed from 1e to 2e to 3e. In 1e, all clerics were the same: same weapon limitations (though evil clerics could use poision), same spell choices, same everything. 2e started to differentiate them with the creation of spheres for their magic. 3e made the differences even more important, so that no two clerics were really the same.
That is what has finally happened in 4e to fighters, I think. No two fighters are exactly, or essentially, the same any more. And that is an improvement that is long overdue.
So yes, on the surface, the elimination of the BAB may seem unreasonable or even stupid, but if you dig a little deeper, I think you will see the method in the WotC's madness. It sounds just fine to me, and I am willing to bet that once I see it in play, I'll be even more convinced that WotC was right in making this change.
Arilon