If it is truly sincere, then I can't see how it is anything but a progressive step. As long as there is no particular racial or political propaganda, I have no problem with it. Surely any (sincerely) peaceful message is good?
I do not agree with many of Iran's policies (if any), but in the current climate any attempt to defuse animosity should be welcomed, in my opinion.
All the same, I'll stick with Her Majesty's speech!