In another sense, all artistic products have some elements of novelty, however minor, just as they all have elements of the familiar. A particular arrangement of words in a novel hasn't seen the light of say, even if the words themselves are trite and uninspired. Even an exact repetition is new as a repetition, and in terms of its context, effects, its baptism of the 'original' as an original (i.e. it becomes an original only when copied). The key thing is deciding whether the new elements are significant and in some way inaugural.
Having said that, there is no reason why newness is automaticaly to be marked with a tick, as positive. As someone once wrote 'Something is no more good because it is new than good because it is near'. Novelty of a certain kind is easy. Buy a duck from Waitrose, stick a plastic dolls head on it and wear it as a hat. The point is how to differentiate genuine novelty from mere 'being different'. The commodity, for example, must differentiate itself from competitors by some gimmick, by a name, a feature whose only function is differentiation and therefore has no positive content. A 'newness' which is simply difference in time (i.e., difference not from competitors but from the old) would be empty in the same way as the difference of the commodity - difference for the sake of differentiation.
The genuinely new is not necessarily opposed to the old either. In fact, the New is opposed not to the old but to the present. If we think of the new in terms of breaking with the present - the status quo, the customary - then movements like Modernism, or the Renaissance have used the remote past (the old) as their starting point. Not yesterday (the immediate past), but a distant past, whose difference can be mobilised to challenge what exists.The radical past is a way of displacing and estranging the present.
Lastly, the new does not have to mean something wholly unprecedented. It is often about renewal. The renewal of theatre, for example, might be about returning to the originary spirit of theatre by making radical formal changes - Peter Brooke's empty stage. Formal innovation is in the service of the origin. The new is actually a return to the source - not by repeating the external forms, the props, the trappings of the source (Shakespeare's Globe?) but the spirit. The origin, which is in a sense very old, remote, can only be maintained by innovation.
n.b see here under 'Unoriginal'