Again, that is what escrow is for. The concept of needing the chargeback/reversal capability is not required. Using escrow allows for consumer protection, even better than the ability to request a chargeback. Rather than paying then (possibly) fighting for your money back by proving something went wrong, instead the transaction is just held in escrow until parties are satisfied that everything is right. If it isn't, then the transaction is cancelled (?). (That's one point of the escrow [m-of-n] option that I have not been able to clear up for me - what happens if you don't get m-of-n parties to agree? Does the transaction automatically get cancelled after a point in time?)
Some sort of escrow system I think would be fine, but that would be a system built on top of the bitcoin system. And I can definitely see it as an improvement on the current ridiculously stupid and unfair chargeback system.
There are a few things to keep in mind, however. First, most consumers will not go back in and confirm delivery after they get the goods. That takes work. Second, if it is easy for consumers to rip off merchants by claiming no delivery, then many will, which brings us right back to the current problem that the "irreversible" part of BTC is supposed to solve.
Thus, we are back to the same problem. Honest consumers are wary of buying with BTC without the ability to reverse things, and merchants don't like a system that will let dishonest consumers rip them off. an escrow system won't solve that basic dilemma. It may just make things better.