Has anyone noticed, or commented on, the fact that if the No Perfect World argument is sound, then Heaven is impossible? I suspect that philosophers who regard it as a logic puzzle don't care, but Christian apologists probably ought to. Yes, even an eternity of perfect bliss in communion with God can alway be improved upon. Perhaps by adding adequate parking...
But the doctrine of heaven isn't about a perfect world (in the sense relevant to the argument); it's about a particular state of life in this world. Indeed, that's the whole point of doctrine; it isn't supposed to be a hypothetical about what would be the case if this world were perfect, but a promise about what can be the case in this world (under a certain set of conditions). And, indeed, it traditionally isn't even intended to be a perfect state of life, except in the sense of being completely fulfilling (since it involves the sort of union with God for which we were intended); there's nothing in the traditional doctrine to say that it is beyond divine omnipotence to make a creature that can experience a heavenly state of life even better than any human being could possibly experience.
So the No Perfect World argument (by which is meant a particular defense against the argument from evil; it is discussed here and here) doesn't really have any bearing on the issue of Heaven. Of course, as my readers know, I don't have any particular commitment to this response to the argument from evil, since I think such defenses superfluous (and I don't think this one particularly impressive or even remotely important except to the extent it points out that supporters of the argument from evil are generally not as clear about what they mean by gratuitous evil as they pretend). But I think the heaven issue isn't one that really arises here.