I have mixed feelings concerning the name, should it be used. On one hand 'Dredd' is a cool succinct name for a film, and putting emphasis on the name make one think of that slightly different spelt word which sounds exactly the same... an emotion he inspires on perps and many citizens as a whole.
On the other hand, one of the main themes of Dredd is that he is a judge, and not just a judge but the archetype judge that many aspire to be. You never see his face completely, and as such you could view him as a kind of avatar of Judgement itself.
As such, I think they should keep with the full title, 'Judge Dredd'.
Not that I'd lose any sleep either way. As I said 'DREDD' alone is pretty cool. I suppose if a lot of the film is from Anderson's point of view that would make sense as the judges usually refer to each other by their Surnames without the 'judge' prefix, even first names in some cases.